diff --git a/examples/aliyun/oss/bucket.rb b/examples/aliyun/oss/bucket.rb
index 5d17923..eea6c48 100644
--- a/examples/aliyun/oss/bucket.rb
+++ b/examples/aliyun/oss/bucket.rb
@@ -4,7 +4,7 @@
 require 'yaml'
 require 'aliyun/oss'
 
-# 初始化OSS client
+# Initialize OSS client
 Aliyun::Common::Logging.set_log_level(Logger::DEBUG)
 conf_file = '~/.oss.yml'
 conf = YAML.load(File.read(File.expand_path(conf_file)))
@@ -15,7 +15,7 @@
   :access_key_secret => conf['access_key_secret'])
 bucket = client.get_bucket(conf['bucket'])
 
-# 辅助打印函数
+# print helper function
 def demo(msg)
   puts "######### #{msg} ########"
   puts
@@ -24,13 +24,13 @@ def demo(msg)
   puts
 end
 
-# 列出当前所有的bucket
+# list all buckets
 demo "List all buckets" do
   buckets = client.list_buckets
   buckets.each{ |b| puts "Bucket: #{b.name}"}
 end
 
-# 创建bucket，如果同名的bucket已经存在，则创建会失败
+# create bucket. If the bucket already exists, the creation will fail
 demo "Create bucket" do
   begin
     bucket_name = 't-foo-bar'
@@ -41,7 +41,7 @@ def demo(msg)
   end
 end
 
-# 向bucket中添加5个空的object:
+# add 5 empty objects into bucket:
 # foo/obj1, foo/bar/obj1, foo/bar/obj2, foo/xxx/obj1
 
 demo "Put objects before list" do
@@ -52,7 +52,7 @@ def demo(msg)
   bucket.put_object('中国の')
 end
 
-# list bucket下所有objects
+# list bucket's all objects
 demo "List first 10 objects" do
   objects = bucket.list_objects
 
@@ -61,7 +61,7 @@ def demo(msg)
   end
 end
 
-# list bucket下所有前缀为foo/bar/的object
+# list bucket's all object whose name has the prefix foo/bar/
 demo "List first 10 objects with prefix 'foo/bar/'" do
   objects = bucket.list_objects(:prefix => 'foo/bar/')
 
@@ -70,18 +70,17 @@ def demo(msg)
   end
 end
 
-# 获取object的common prefix，common prefix是指bucket下所有object（也可
-# 以指定特定的前缀）的公共前缀，这在object数量巨多的时候很有用，例如有
-# 如下的object：
+# get common prefix of the object. Common prefix object is the object whose name is the common prefix of some other objects in the bucket.
+# Essentially it's a 'folder' in the bucket.
+# For example, if we have the following objects:
 #     /foo/bar/obj1
 #     /foo/bar/obj2
 #     ...
 #     /foo/bar/obj9999999
 #     /foo/xx/
-# 指定foo/为prefix，/为delimiter，则返回的common prefix为
-# /foo/bar/, /foo/xxx/
-# 这可以表示/foo/目录下的子目录。如果没有common prefix，你可能要遍历所
-# 有的object来找公共的前缀
+# Specify the prefix as foo/ and delimiter as '/', then the retirned common prefix is 
+# /foo/bar/ and /foo/xxx/
+# They could represent the subfolder of '/foo' folder. It's a efficient way to enumerate all files under a folder by specifying the common prefix.
 
 demo "List first 10 objects/common prefixes" do
   objects = bucket.list_objects(:prefix => 'foo/', :delimiter => '/')
@@ -95,7 +94,7 @@ def demo(msg)
   end
 end
 
-# 获取/设置Bucket属性: ACL, Logging, Referer, Website, LifeCycle, CORS
+# get/set Bucket attributes: ACL, Logging, Referer, Website, LifeCycle, CORS
 demo "Get/Set bucket properties: ACL/Logging/Referer/Website/Lifecycle/CORS" do
   puts "Bucket acl before: #{bucket.acl}"
   bucket.acl = Aliyun::OSS::ACL::PUBLIC_READ
diff --git a/examples/aliyun/oss/callback.rb b/examples/aliyun/oss/callback.rb
index b35338b..0b5c105 100644
--- a/examples/aliyun/oss/callback.rb
+++ b/examples/aliyun/oss/callback.rb
@@ -6,14 +6,13 @@
 require 'aliyun/oss'
 
 ##
-# 用户在上传文件时可以指定“上传回调”，这样在文件上传成功后OSS会向用户
-# 提供的服务器地址发起一个HTTP POST请求，相当于一个通知机制。用户可以
-# 在收到回调的时候做相应的动作。
-# 1. 如何接受OSS的回调可以参考代码目录下的
+# User could specify callback  when uploading a file so that OSS will issue a POST request to that callback url upon a successful file upload.
+# This is one way of notification and user could do proper action on that callback request.
+# 1. Check out the following file to know more about how to handle OSS's callback request.
 #    rails/aliyun_oss_callback_server.rb
-# 2. 只有put_object和resumable_upload支持上传回调
+# 2. Only put_object and resumable_upload support upload callback.
 
-# 初始化OSS client
+# Initialize OSS client
 Aliyun::Common::Logging.set_log_level(Logger::DEBUG)
 conf_file = '~/.oss.yml'
 conf = YAML.load(File.read(File.expand_path(conf_file)))
@@ -23,7 +22,7 @@
   :access_key_id => conf['access_key_id'],
   :access_key_secret => conf['access_key_secret']).get_bucket(conf['bucket'])
 
-# 辅助打印函数
+# print helper function
 def demo(msg)
   puts "######### #{msg} ########"
   puts
diff --git a/examples/aliyun/oss/object.rb b/examples/aliyun/oss/object.rb
index a299ff3..790342d 100644
--- a/examples/aliyun/oss/object.rb
+++ b/examples/aliyun/oss/object.rb
@@ -4,7 +4,7 @@
 require 'yaml'
 require 'aliyun/oss'
 
-# 初始化OSS client
+# Initialize OSS client
 Aliyun::Common::Logging.set_log_level(Logger::DEBUG)
 conf_file = '~/.oss.yml'
 conf = YAML.load(File.read(File.expand_path(conf_file)))
@@ -14,7 +14,7 @@
   :access_key_id => conf['access_key_id'],
   :access_key_secret => conf['access_key_secret']).get_bucket(conf['bucket'])
 
-# 辅助打印函数
+# print helper function
 def demo(msg)
   puts "######### #{msg} ########"
   puts
@@ -23,8 +23,8 @@ def demo(msg)
   puts
 end
 
-# 上传一个object
-# 流式上传请参考：examples/streaming.rb
+# upload an object
+# Check out examples/streaming.rb for streaming upload example.
 demo "Put object from input" do
   bucket.put_object('files/hello') do |content|
     content << 'hello world.'
@@ -32,15 +32,15 @@ def demo(msg)
   puts "Put object: files/hello"
 end
 
-# 上传一个文件
-# 断点续传请参考：examples/resumable_upload.rb
+# upload an object
+# Check out examples/resumable_upload.rb for resumable upload example.
 demo "Put object from local file" do
   File.open('/tmp/x', 'w'){ |f| f.write("hello world\n") }
   bucket.put_object('files/world', :file => '/tmp/x')
   puts "Put object: files/world"
 end
 
-# 创建一个Appendable object
+# Create an Appendable object
 demo "Create appendable object" do
 size = bucket.get_object('files/appendable').size rescue 0
   bucket.append_object('files/appendable', size) do |content|
@@ -49,8 +49,8 @@ def demo(msg)
   puts "Append object: files/appendable"
 end
 
-# 向files/appendable中追加内容
-# 首先要获取object当前的长度
+# append content into files/appendable.
+# Get the object's current length.
 demo "Append to object" do
   size = bucket.get_object('files/appendable').size
   bucket.append_object('files/appendable', size) do |content|
@@ -59,7 +59,7 @@ def demo(msg)
   puts "Append object: files/appendable"
 end
 
-# 使用错误的position进行追加会失败
+# Append will fail if using wrong position
 demo "Append with wrong pos" do
   begin
     bucket.append_object('files/appendable', 0) do |content|
@@ -70,7 +70,7 @@ def demo(msg)
   end
 end
 
-# 向一个normal object中追加内容会失败
+# Appending to normal object will fail
 demo "Append to normal object(fail)" do
   begin
     bucket.append_object('files/hello', 0) do |content|
@@ -81,13 +81,13 @@ def demo(msg)
   end
 end
 
-# 拷贝一个object
+# copy an object
 demo "Copy object" do
   bucket.copy_object('files/hello', 'files/copy')
   puts "Copy object files/hello => files/copy"
 end
 
-# 拷贝一个appendable object会失败
+# copying an appendable object will fail
 demo "Copy appendable object(fail)" do
   begin
     bucket.copy_object('files/appendable', 'files/copy')
@@ -96,8 +96,8 @@ def demo(msg)
   end
 end
 
-# 下载一个object：流式处理
-# 流式下载请参考：examples/streaming.rb
+# download an OSS object into memory
+# Check out examples/streaming.rb for streaming download examples.
 demo "Get object: handle content" do
   total_size = 0
   bucket.get_object('files/hello') do |chunk|
@@ -106,27 +106,27 @@ def demo(msg)
   puts "Total size: #{total_size}"
 end
 
-# 下载一个object：下载到文件中
+# download an OSS object into local file
 demo "Get object to local file" do
   bucket.get_object('files/hello', :file => '/tmp/hello')
   puts "Get object: files/hello => /tmp/hello"
 end
 
-# 删除一个object
+# delete an object
 demo "Delete object" do
   bucket.delete_object('files/world')
   puts "Delete object: files/world"
 end
 
-# 删除一个不存在的object返回OK
-# 这意味着delete_object是幂等的，在删除失败的时候可以不断重试，直到成
-# 功，成功意味着object已经不存在
+# Delete an non-existing object and it should return OK.
+# So delete_object is idempotent and you can retry delete_object until success if it fails.
+# It means the object does not exist if delete_object return OK.
 demo "Delete a non-existent object(OK)" do
   bucket.delete_object('non-existent-object')
   puts "Delete object: non-existent-object"
 end
 
-# 设置Object metas
+# Set Object metas
 demo "Put objec with metas" do
   bucket.put_object(
     'files/hello',
@@ -139,7 +139,7 @@ def demo(msg)
   puts "Object metas: #{o.metas}"
 end
 
-# 修改Object metas
+# Modify Object metas
 demo "Update object metas" do
   bucket.update_object_metas(
     'files/hello', {'year' => '2016', 'people' => 'jack'})
@@ -147,7 +147,7 @@ def demo(msg)
   puts "Meta changed: #{o.metas}"
 end
 
-# 设置Object的ACL
+# Set Object的ACL
 
 demo "Set object ACL" do
   puts "Object acl before: #{bucket.get_object_acl('files/hello')}"
@@ -155,7 +155,7 @@ def demo(msg)
   puts "Object acl now: #{bucket.get_object_acl('files/hello')}"
 end
 
-# 指定条件get_object
+# get_object with conditions
 demo "Get object with conditions" do
   o = bucket.get_object('files/hello')
 
diff --git a/examples/aliyun/oss/resumable_download.rb b/examples/aliyun/oss/resumable_download.rb
index fac4b12..92b3f30 100644
--- a/examples/aliyun/oss/resumable_download.rb
+++ b/examples/aliyun/oss/resumable_download.rb
@@ -4,7 +4,7 @@
 require 'yaml'
 require 'aliyun/oss'
 
-# 初始化OSS Bucket
+# Initialize OSS Bucket
 Aliyun::Common::Logging.set_log_level(Logger::DEBUG)
 conf_file = '~/.oss.yml'
 conf = YAML.load(File.read(File.expand_path(conf_file)))
@@ -14,7 +14,7 @@
   :access_key_id => conf['access_key_id'],
   :access_key_secret => conf['access_key_secret']).get_bucket(conf['bucket'])
 
-# 辅助打印函数
+# print helper function
 def demo(msg)
   puts "######### #{msg} ########"
   puts
@@ -24,7 +24,7 @@ def demo(msg)
 end
 
 demo "Resumable download" do
-  # 下载一个100M的文件
+  # Download a 100M file
   cpt_file = '/tmp/y.cpt'
   File.delete(cpt_file) if File.exist?(cpt_file)
   start = Time.now
@@ -35,8 +35,8 @@ def demo(msg)
   end
   puts "Download complete. Cost: #{Time.now - start} seconds."
 
-  # 测试方法：
+  # test method：
   # 1. ruby examples/resumable_download.rb
-  # 2. 过几秒后用Ctrl-C中断下载
-  # 3. ruby examples/resumable_download.rb恢复下载
+  # 2. after a few seconds, type Ctrl-C to disrupt the download.
+  # 3. ruby examples/resumable_download.rb to recover the download
 end
diff --git a/examples/aliyun/oss/resumable_upload.rb b/examples/aliyun/oss/resumable_upload.rb
index ae53a9e..a455ff2 100644
--- a/examples/aliyun/oss/resumable_upload.rb
+++ b/examples/aliyun/oss/resumable_upload.rb
@@ -4,7 +4,7 @@
 require 'yaml'
 require 'aliyun/oss'
 
-# 初始化OSS Bucket
+# Initialize OSS Bucket
 Aliyun::Common::Logging.set_log_level(Logger::DEBUG)
 conf_file = '~/.oss.yml'
 conf = YAML.load(File.read(File.expand_path(conf_file)))
@@ -14,7 +14,7 @@
   :access_key_id => conf['access_key_id'],
   :access_key_secret => conf['access_key_secret']).get_bucket(conf['bucket'])
 
-# 辅助打印函数
+# print helper function
 def demo(msg)
   puts "######### #{msg} ########"
   puts
@@ -25,7 +25,7 @@ def demo(msg)
 
 demo "Resumable upload" do
   puts "Generate file: /tmp/x, size: 100MB"
-  # 生成一个100M的文件
+  # Create a 100M file
   File.open('/tmp/x', 'w') do |f|
     (1..1024*1024).each{ |i| f.puts i.to_s.rjust(99, '0') }
   end
@@ -33,7 +33,7 @@ def demo(msg)
   cpt_file = '/tmp/x.cpt'
   File.delete(cpt_file) if File.exist?(cpt_file)
 
-  # 上传一个100M的文件
+  # Upload a 100M file
   start = Time.now
   puts "Start upload: /tmp/x => resumable"
   bucket.resumable_upload(
@@ -42,8 +42,8 @@ def demo(msg)
   end
   puts "Upload complete. Cost: #{Time.now - start} seconds."
 
-  # 测试方法：
+  # Test steps:
   # 1. ruby examples/resumable_upload.rb
-  # 2. 过几秒后用Ctrl-C中断上传
-  # 3. ruby examples/resumable_upload.rb恢复上传
+  # 2. Type Ctrl-C to distrupt the upload after a few seconds
+  # 3. run ruby examples/resumable_upload.rb to recover the upload
 end
diff --git a/examples/aliyun/oss/streaming.rb b/examples/aliyun/oss/streaming.rb
index a7450ac..dc108ee 100644
--- a/examples/aliyun/oss/streaming.rb
+++ b/examples/aliyun/oss/streaming.rb
@@ -5,24 +5,20 @@
 require 'aliyun/oss'
 
 ##
-# 一般来说用户在上传object和下载object时只需要指定文件名就可以满足需要：
-# - 在上传的时候client会从指定的文件中读取数据上传到OSS
-# - 在下载的时候client会把从OSS下载的数据写入到指定的文件中
+# Generally speaking, when a user uploads or downloads objects with specifying a file:
+# - In upload, client will upload the data of the file to OSS.
+# - In download, client will download the data from OSS to the file locally.
 #
-# 在某些情况下用户可能会需要流式地上传和下载：
-# - 用户要写入到object中的数据不能立即得到全部，而是从网络中流式获取，
-#   然后再一段一段地写入到OSS中
-# - 用户要写入到object的数据是经过运算得出，每次得到一部分，用户不希望
-#   保留所有的数据然后一次性写入到OSS
-# - 用户下载的object很大，用户不希望一次性把它们下载到内存中，而是希望
-#   获取一部分就处理一部分；用户也不希望把它先下载到文件中，然后再从文
-#   件中读出来处理，这样会让数据经历不必要的拷贝
+# However in some scenarios, users may want to download or upload data in streaming:
+# - Users cannot get the whole data for uploading, instead each time they get the partial data from up streaming and write it into OSS.
+# - The data users want to write is computed and each compute just returns partial data. Typically Users dont want to compute all data and then write them as the whole
+#   to OSS. Instead they wantt o compute some data and write the result to OSS immediately.
+# - The object users want to download is too big to hold in memory. They want to download some data and then processs them without saving to local file.
 #
-# 当然，对于流式上传的需求，我们可以使用OSS的appendable object来满足。
-# 但是即使是normal object，利用sdk的streaming功能，也可以实现流式上传
-# 和下载。
+# Of course, for streaming upload scenario, we can leverage appendable object to solve.
+# However, even for normal object, by using SDK's streaming APIs, you can also achieve the streaming upload or download.
 
-# 初始化OSS client
+# Initialize OSS client
 Aliyun::Common::Logging.set_log_level(Logger::DEBUG)
 conf_file = '~/.oss.yml'
 conf = YAML.load(File.read(File.expand_path(conf_file)))
@@ -32,7 +28,7 @@
   :access_key_id => conf['access_key_id'],
   :access_key_secret => conf['access_key_secret']).get_bucket(conf['bucket'])
 
-# 辅助打印函数
+# print helper function
 def demo(msg)
   puts "######### #{msg} ########"
   puts
@@ -41,9 +37,9 @@ def demo(msg)
   puts
 end
 
-# 例子1: 归并排序
-# 有两个文件sort.1, sort.2，它们分别存了一些从小到大排列的整数，每个整
-# 数1行，现在要将它们做归并排序的结果上传到OSS中，命名为sort.all
+# Example1: merge sort
+# There're two files sort.1 and sort.2 which have the sorted int. Every int occupies one line.
+# Now you need to merge sort the two files into one file and uploaded it to OSS.
 
 local_1, local_2 = 'sort.1', 'sort.2'
 result_object = 'sort.all'
@@ -83,29 +79,29 @@ def demo(msg)
 
   puts "Put object: #{result_object}"
 
-  # 将文件下载下来查看
+  # download the file and print the content
   bucket.get_object(result_object, :file => result_object)
   puts "Get object: #{result_object}"
   puts "Content: #{File.read(result_object)}"
 end
 
-# 例子2: 下载进度条
-# 下载一个大文件（10M），在下载的过程中打印下载进度
+# Example 2: download progress bar
+# Download a 10M file and print the download progress
 
 large_file = 'large_file'
 
 demo "Streaming download" do
   puts "Begin put object: #{large_file}"
-  # 利用streaming上传
+  # Leverage streaming upload
   bucket.put_object(large_file) do |stream|
     10.times { stream << "x" * (1024 * 1024) }
   end
 
-  # 查看object大小
+  # check object size
   object_size = bucket.get_object(large_file).size
   puts "Put object: #{large_file}, size: #{object_size}"
 
-  # 流式下载文件，仅打印进度，不保存文件
+  # streaming download file, print the progress, but not save the file
   def to_percentile(v)
     "#{(v * 100.0).round(2)} %"
   end
@@ -114,7 +110,7 @@ def to_percentile(v)
   last_got, got = 0, 0
   bucket.get_object(large_file) do |chunk|
     got += chunk.size
-    # 仅在下载进度大于10%的时候打印
+    # only print the progress when the progress is more than 10%.
     if (got - last_got).to_f / object_size > 0.1
       puts "Progress: #{to_percentile(got.to_f / object_size)}"
       last_got = got
diff --git a/examples/aliyun/oss/using_sts.rb b/examples/aliyun/oss/using_sts.rb
index 29ede9e..a750ae1 100644
--- a/examples/aliyun/oss/using_sts.rb
+++ b/examples/aliyun/oss/using_sts.rb
@@ -5,12 +5,12 @@
 require 'aliyun/sts'
 require 'aliyun/oss'
 
-# 初始化OSS client
+# Initialize OSS client
 Aliyun::Common::Logging.set_log_level(Logger::DEBUG)
 conf_file = '~/.sts.yml'
 conf = YAML.load(File.read(File.expand_path(conf_file)))
 
-# 辅助打印函数
+# print helper function
 def demo(msg)
   puts "######### #{msg} ########"
   puts
diff --git a/examples/aliyun/sts/assume_role.rb b/examples/aliyun/sts/assume_role.rb
index 3728995..238cd1e 100644
--- a/examples/aliyun/sts/assume_role.rb
+++ b/examples/aliyun/sts/assume_role.rb
@@ -11,7 +11,7 @@
   :access_key_id => conf['access_key_id'],
   :access_key_secret => conf['access_key_secret'])
 
-# 辅助打印函数
+# print helper function
 def demo(msg)
   puts "######### #{msg} ########"
   puts
diff --git a/lib/aliyun/common/logging.rb b/lib/aliyun/common/logging.rb
index 46e339c..14b5325 100644
--- a/lib/aliyun/common/logging.rb
+++ b/lib/aliyun/common/logging.rb
@@ -20,12 +20,12 @@ def self.set_log_level(level)
         Logging.logger.level = level
       end
 
-      # 设置日志输出的文件
+      # set logger output file
       def self.set_log_file(file)
         @log_file = file
       end
 
-      # 获取logger
+      # get logger
       def logger
         Logging.logger
       end
diff --git a/lib/aliyun/oss/bucket.rb b/lib/aliyun/oss/bucket.rb
index 2b775e1..d79cc82 100644
--- a/lib/aliyun/oss/bucket.rb
+++ b/lib/aliyun/oss/bucket.rb
@@ -3,11 +3,11 @@
 module Aliyun
   module OSS
     ##
-    # Bucket是用户的Object相关的操作的client，主要包括三部分功能：
-    # 1. bucket相关：获取/设置bucket的属性（acl, logging, referer,
-    #    website, lifecycle, cors）
-    # 2. object相关：上传、下载、追加、拷贝object等
-    # 3. multipart相关：断点续传、断点续载
+    # Bucket is the class for object related operations. It consists of three major functions:
+    # 1. bucket related：Gets/Sets bucket settings (e.g. acl, logging, referer,
+    #    website, lifecycle, cors, etc）
+    # 2. object related：Upload, download, append, copy object, etc
+    # 3. multipart related：upload with checkpoint, download with checkpoint.
     class Bucket < Common::Struct::Base
 
       attrs :name, :location, :creation_time
@@ -17,28 +17,28 @@ def initialize(opts = {}, protocol = nil)
         @protocol = protocol
       end
 
-      ### Bucket相关的API ###
+      ### Bucket related API ###
 
-      # 获取Bucket的ACL
+      # Gets Bucket ACL
       # @return [String] Bucket的{OSS::ACL ACL}
       def acl
         @protocol.get_bucket_acl(name)
       end
 
-      # 设置Bucket的ACL
+      # Sets Bucket ACL
       # @param acl [String] Bucket的{OSS::ACL ACL}
       def acl=(acl)
         @protocol.put_bucket_acl(name, acl)
       end
 
-      # 获取Bucket的logging配置
-      # @return [BucketLogging] Bucket的logging配置
+      # Gets Bucket logging config
+      # @return [BucketLogging] Bucket logging config
       def logging
         @protocol.get_bucket_logging(name)
       end
 
-      # 设置Bucket的logging配置
-      # @param logging [BucketLogging] logging配置
+      # Sets Bucket logging config
+      # @param logging [BucketLogging] logging config
       def logging=(logging)
         if logging.enabled?
           @protocol.put_bucket_logging(name, logging)
@@ -47,8 +47,8 @@ def logging=(logging)
         end
       end
 
-      # 获取Bucket的website配置
-      # @return [BucketWebsite] Bucket的website配置
+      # Gets Bucket website config
+      # @return [BucketWebsite] Bucket website config
       def website
         begin
           w = @protocol.get_bucket_website(name)
@@ -59,8 +59,8 @@ def website
         w || BucketWebsite.new
       end
 
-      # 设置Bucket的website配置
-      # @param website [BucketWebsite] website配置
+      # Sets Bucket website config
+      # @param website [BucketWebsite] website config
       def website=(website)
         if website.enabled?
           @protocol.put_bucket_website(name, website)
@@ -69,21 +69,20 @@ def website=(website)
         end
       end
 
-      # 获取Bucket的Referer配置
-      # @return [BucketReferer] Bucket的Referer配置
+      # Gets Bucket referer config
+      # @return [BucketReferer] Bucket referer config
       def referer
         @protocol.get_bucket_referer(name)
       end
 
-      # 设置Bucket的Referer配置
-      # @param referer [BucketReferer] Referer配置
+      # Sets Bucket referer config
+      # @param referer [BucketReferer] Referer config
       def referer=(referer)
         @protocol.put_bucket_referer(name, referer)
       end
 
-      # 获取Bucket的生命周期配置
-      # @return [Array<OSS::LifeCycleRule>] Bucket的生命周期规则，如果
-      #  当前Bucket未设置lifecycle，则返回[]
+      # GETS Bucket's lifecycle config
+      # @return [Array<OSS::LifeCycleRule>] Bucket's lifecycle config, if it's not set, return [].
       def lifecycle
         begin
           r = @protocol.get_bucket_lifecycle(name)
@@ -94,11 +93,10 @@ def lifecycle
         r || []
       end
 
-      # 设置Bucket的生命周期配置
-      # @param rules [Array<OSS::LifeCycleRule>] 生命
-      #  周期配置规则
-      # @see OSS::LifeCycleRule 查看如何设置生命周期规则
-      # @note 如果rules为空，则会删除这个bucket上的lifecycle配置
+      # Sets Bucket's lifecycle config
+      # @param rules [Array<OSS::LifeCycleRule>] lifecycle rule config.
+      # @see OSS::LifeCycleRule for how to set lifecycle rules.
+      # @note if rules is empty, the existing lifecycle config will be deleted.
       def lifecycle=(rules)
         if rules.empty?
           @protocol.delete_bucket_lifecycle(name)
@@ -107,9 +105,8 @@ def lifecycle=(rules)
         end
       end
 
-      # 获取Bucket的跨域资源共享(CORS)的规则
-      # @return [Array<OSS::CORSRule>] Bucket的CORS规则，如果当前
-      #  Bucket未设置CORS规则，则返回[]
+      # Gets Bucket's CORS rules
+      # @return [Array<OSS::CORSRule>] Bucket's CORS rules. If it's not set, returns [].
       def cors
         begin
           r = @protocol.get_bucket_cors(name)
@@ -120,9 +117,9 @@ def cors
         r || []
       end
 
-      # 设置Bucket的跨域资源共享(CORS)的规则
-      # @param rules [Array<OSS::CORSRule>] CORS规则
-      # @note 如果rules为空，则会删除这个bucket上的CORS配置
+      # Sets Bucket CORS rules
+      # @param rules [Array<OSS::CORSRule>] CORS rules
+      # @note If rules are empty, it will delete the existing CORS config.
       def cors=(rules)
         if rules.empty?
           @protocol.delete_bucket_cors(name)
@@ -131,30 +128,27 @@ def cors=(rules)
         end
       end
 
-      ### Object相关的API ###
+      ### Object related API ###
 
 
-      # 列出bucket中的object
-      # @param opts [Hash] 查询选项
-      # @option opts [String] :prefix 返回的object的前缀，如果设置则只
-      #  返回那些名字以它为前缀的object
-      # @option opts [String] :marker 如果设置，则只返回名字在它之后
-      #  （字典序，不包含marker）的object
-      # @option opts [String] :delimiter 用于获取公共前缀的分隔符，从
-      #  前缀后面开始到第一个分隔符出现的位置之前的字符，作为公共前缀。
+      # Lists objects in the bucket
+      # @param opts [Hash] options for the list operation
+      # @option opts [String] :prefix object prefix. If set, it will only return objects whose key has the prefix.
+      # @option opts [String] :marker object marker. If set, it will only return objects whose key is greater than the marker.
+      # @option opts [String] :delimiter the separator for getting common prefix. The common prefixes are the objects 
+      # whose key starting with prefix and ending with the delimiter.
       # @example
-      #  假设我们有如下objects:
+      #  If we have the following objects:
       #     /foo/bar/obj1
       #     /foo/bar/obj2
       #     ...
       #     /foo/bar/obj9999999
       #     /foo/xxx/
-      #  用'foo/'作为前缀, '/'作为分隔符, 则得到的公共前缀是：
-      #  '/foo/bar/', '/foo/xxx/'。它们恰好就是目录'/foo/'下的所有子目
-      #  录。用delimiter获取公共前缀的方法避免了查询当前bucket下的所有
-      #   object（可能数量巨大），是用于模拟目录结构的常用做法。
-      # @return [Enumerator<Object>] 其中Object可能是{OSS::Object}，也
-      #  可能是{String}，此时它是一个公共前缀
+      #  Use 'foo/' as prefix and '/' as delimiter, then the common prefixes are:
+      #  '/foo/bar/', '/foo/xxx/'. They're the subdirectories of directory '/foo/'.
+      #  Use prefix and delimiter for getting common prefix could avoid querying all the objects under the bucket.
+      #  This is the common practise for iterating the directory structures.
+      # @return [Enumerator<Object>] the object could be {OSS::Object} or {String}. In latter case it's the common prefix.
       # @example
       #  all = bucket.list_objects
       #  all.each do |i|
@@ -169,31 +163,29 @@ def list_objects(opts = {})
           @protocol, name, opts.merge(encoding: KeyEncoding::URL)).to_enum
       end
 
-      # 向Bucket中上传一个object
-      # @param key [String] Object的名字
-      # @param opts [Hash] 上传object时的选项（可选）
-      # @option opts [String] :file 设置所上传的文件
-      # @option opts [String] :content_type 设置所上传的内容的
-      #  Content-Type，默认是application/octet-stream
-      # @option opts [Hash] :metas 设置object的meta，这是一些用户自定
-      #  义的属性，它们会和object一起存储，在{#get_object}的时候会
-      #  返回这些meta。属性的key不区分大小写。例如：{ 'year' => '2015' }
-      # @option opts [Callback] :callback 指定操作成功后OSS的
-      #  上传回调，上传成功后OSS会向用户的应用服务器发一个HTTP POST请
-      #  求，`:callback`参数指定这个请求的相关参数
-      # @option opts [Hash] :headers 指定请求的HTTP Header，不区分大小
-      #  写。这里指定的值会覆盖通过`:content_type`和`:metas`设置的值。
-      # @yield [HTTP::StreamWriter] 如果调用的时候传递了block，则写入
-      #  到object的数据由block指定
-      # @example 流式上传数据
+      # Uploads an object to the bucket
+      # @param key [String] Object key
+      # @param opts [Hash] options for uploading 
+      # @option opts [String] :file local file to upload
+      # @option opts [String] :content_type content to upload
+      #  Content-Type，default is application/octet-stream
+      # @option opts [Hash] :metas object's custom meta,which will be stored with object. 
+      #  They're returned when {#get_object} are called. The custom metadata's key are not case sensitive.
+      #  For example ：{ 'year' => '2015' } is same as {'YEAR' => '2015'}
+      # @option opts [Callback] :callback specifies the callback after the operation succeeds.
+      #  After the upload succeeds, OSS could send a HTTP POST to user's application--the callback parameter specifies parameters of this post request.
+      # @option opts [Hash] :headers specifies the HTTP headers, the headers are case insensitive.
+      #   Its values could overwrite the the value set by `:content_type` and `:metas`.
+      # @yield [HTTP::StreamWriter] if the block is specified, then the object content is specified by thsi block.
+      # @example upload streaming data
       #   put_object('x'){ |stream| 100.times { |i| stream << i.to_s } }
       #   put_object('x'){ |stream| stream << get_data }
-      # @example 上传文件
+      # @example upload file
       #   put_object('x', :file => '/tmp/x')
-      # @example 指定Content-Type和metas
+      # @example specifies Content-Type and metas
       #   put_object('x', :file => '/tmp/x', :content_type => 'text/html',
       #              :metas => {'year' => '2015', 'people' => 'mary'})
-      # @example 指定Callback
+      # @example specifies Callback
       #   callback = Aliyun::OSS::Callback.new(
       #     url: 'http://10.101.168.94:1234/callback',
       #     query: {user: 'put_object'},
@@ -201,12 +193,10 @@ def list_objects(opts = {})
       #   )
       #
       #   bucket.put_object('files/hello', callback: callback)
-      # @raise [CallbackError] 如果文件上传成功而Callback调用失败，抛
-      #  出此错误
-      # @note 如果opts中指定了`:file`，则block会被忽略
-      # @note 如果指定了`:callback`，则可能文件上传成功，但是callback
-      #  执行失败，此时会抛出{OSS::CallbackError}，用户可以选择接住这
-      #  个异常，以忽略Callback调用错误
+      # @raise [CallbackError] If file upload succeeds but callback failed, it will throw this error.
+      # @note If `:file` is specified in opts, then block parameter is ignored.
+      # @note If `:callback` is specified, then it's possibel that file upload succeeds but callback fails, in which case
+      #   the {OSS::CallbackError} is thrown. The call could opt to catch this exception and ignore the callback failure.
       def put_object(key, opts = {}, &block)
         args = opts.dup
 
@@ -225,39 +215,38 @@ def put_object(key, opts = {}, &block)
         end
       end
 
-      # 从Bucket中下载一个object
-      # @param key [String] Object的名字
-      # @param opts [Hash] 下载Object的选项（可选）
-      # @option opts [Array<Integer>] :range 指定下载object的部分数据，
-      #  range应只包含两个数字，表示一个*左开右闭*的bytes range
-      # @option opts [String] :file 指定将下载的object写入到文件中
-      # @option opts [Hash] :condition 指定下载object需要满足的条件
-      #   * :if_modified_since (Time) 指定如果object的修改时间晚于这个值，则下载
-      #   * :if_unmodified_since (Time) 指定如果object从这个时间后再无修改，则下载
-      #   * :if_match_etag (String) 指定如果object的etag等于这个值，则下载
-      #   * :if_unmatch_etag (String) 指定如果object的etag不等于这个值，则下载
-      # @option opts [Hash] :headers 指定请求的HTTP Header，不区分大小
-      #  写。这里指定的值会覆盖通过`:range`和`:condition`设置的值。
-      # @option opts [Hash] :rewrite 指定下载object时Server端返回的响应头部字段的值
-      #   * :content_type (String) 指定返回的响应中Content-Type的值
-      #   * :content_language (String) 指定返回的响应中Content-Language的值
-      #   * :expires (Time) 指定返回的响应中Expires的值
-      #   * :cache_control (String) 指定返回的响应中Cache-Control的值
-      #   * :content_disposition (String) 指定返回的响应中Content-Disposition的值
-      #   * :content_encoding (String) 指定返回的响应中Content-Encoding的值
-      # @return [OSS::Object] 返回Object对象
-      # @yield [String] 如果调用的时候传递了block，则获取到的object的数据交由block处理
-      # @example 流式下载文件
+      # Download an object from the bucket
+      # @param key [String] Object key.
+      # @param opts [Hash] options for downloading objects
+      # @option opts [Array<Integer>] :range specifies the exact offset of the object to download.
+      #  The range should follow the HTTP Range specification (https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Range).
+      # @option opts [String] :file specifies the local file path for store the object to download.
+      # @option opts [Hash] :condition specifies the condition to download the file.
+      #   * :if_modified_since (Time) if the object's last modified time is later than this value, download the object.
+      #   * :if_unmodified_since (Time) if the object's last modified time is earlier than this value, download the object.
+      #   * :if_match_etag (String) if the object's ETag matches this value, download the object.
+      #   * :if_unmatch_etag (String) if the object's ETag does not match this value, download the object.
+      # @option opts [Hash] :headers specifies HTTP headers, they're case insensitive.
+      #  The headers' values could overwrite the values set by `:range` and `:condition`.
+      # @option opts [Hash] :rewrite specifies the headers the OSS server response should contain for the download request.
+      #   * :content_type (String) specifies the response to return Content-Type value
+      #   * :content_language (String) specifies the response to return Content-Language value
+      #   * :expires (Time) specifies the response to return Expires value.
+      #   * :cache_control (String) specifies the response to return Cache-Control value.
+      #   * :content_disposition (String) specifies the response to return Content-Disposition value.
+      #   * :content_encoding (String) specifies the response to return Content-Encoding value.
+      # @return [OSS::Object] returns Object
+      # @yield [String] if the block is specified, then the data will be stored in block.
+      # @example stremaing data download
       #   get_object('x'){ |chunk| handle_chunk_data(chunk) }
-      # @example 下载到本地文件
+      # @example download object to local file
       #   get_object('x', :file => '/tmp/x')
-      # @example 指定检查条件
+      # @example specifies condition
       #   get_object('x', :file => '/tmp/x', :condition => {:if_match_etag => 'etag'})
-      # @example 指定重写响应的header信息
+      # @example specifies rewrite header information.
       #   get_object('x', :file => '/tmp/x', :rewrite => {:content_type => 'text/html'})
-      # @note 如果opts中指定了`:file`，则block会被忽略
-      # @note 如果既没有指定`:file`也没有指定block，则只获取Object
-      #  meta而不下载Object内容
+      # @note If opts contains `:file`，then block is ignored.
+      # @note If neither `:file` nor block is specified, then only object meta is returned (no content)
       def get_object(key, opts = {}, &block)
         obj = nil
         file = opts[:file]
@@ -276,14 +265,14 @@ def get_object(key, opts = {}, &block)
         obj
       end
 
-      # 更新Object的metas
-      # @param key [String] Object的名字
-      # @param metas [Hash] Object的meta
-      # @param conditions [Hash] 指定更新Object meta需要满足的条件，
-      #  同{#get_object}
-      # @return [Hash] 更新后文件的信息
-      #  * :etag [String] 更新后文件的ETag
-      #  * :last_modified [Time] 更新后文件的最后修改时间
+      # Updates Object's metas
+      # @param key [String] Object's name
+      # @param metas [Hash] Object's meta
+      # @param conditions [Hash] Specifies the condition to update Object meta.
+      #  It's same as the one in {#get_object}
+      # @return [Hash] updated file metadatas
+      #  * :etag [String] new ETag
+      #  * :last_modified [Time] updated last modified time
       def update_object_metas(key, metas, conditions = {})
         @protocol.copy_object(
           name, key, key,
@@ -292,9 +281,9 @@ def update_object_metas(key, metas, conditions = {})
           :condition => conditions)
       end
 
-      # 判断一个object是否存在
-      # @param key [String] Object的名字
-      # @return [Boolean] 如果Object存在返回true，否则返回false
+      # checks if an object exists or not.
+      # @param key [String] Object key.
+      # @return [Boolean]  If object exists, returns true; otherwise returns false.
       def object_exists?(key)
         begin
           get_object(key)
@@ -309,28 +298,28 @@ def object_exists?(key)
 
       alias :object_exist? :object_exists?
 
-      # 向Bucket中的object追加内容。如果object不存在，则创建一个
-      # Appendable Object。
-      # @param key [String] Object的名字
-      # @param opts [Hash] 上传object时的选项（可选）
-      # @option opts [String] :file 指定追加的内容从文件中读取
-      # @option opts [String] :content_type 设置所上传的内容的
-      #  Content-Type，默认是application/octet-stream
-      # @option opts [Hash] :metas 设置object的meta，这是一些用户自定
-      #  义的属性，它们会和object一起存储，在{#get_object}的时候会
-      #  返回这些meta。属性的key不区分大小写。例如：{ 'year' => '2015' }
-      # @option opts [Hash] :headers 指定请求的HTTP Header，不区分大小
-      #  写。这里指定的值会覆盖通过`:content_type`和`:metas`设置的值。
-      # @example 流式上传数据
+      # Appends content to the object in a bucket. If the object does not exist, create a new one.
+      # Appendable Object.
+      # @param key [String] Object key
+      # @param opts [Hash] opts for appending the object (optional)
+      # @option opts [String] :file specifies the local file to read from for the appending.
+      # @option opts [String] :content_type sets the content-type for the upload
+      #  Content-Type，default is application/octet-stream
+      # @option opts [Hash] :metas Sets object meta. These user custom metadata will be stored with object.
+      #  And {#get_object} would return these meta.
+      #  metas' key are case insensitive. For example:{ 'year' => '2015' }
+      # @option opts [Hash] :headers specifies HTTP header, it's case insenstive.
+      #  The values would overwrite the one set by `:content_type` and `:metas`.
+      # @example append streaming data.
       #   pos = append_object('x', 0){ |stream| 100.times { |i| stream << i.to_s } }
       #   append_object('x', pos){ |stream| stream << get_data }
-      # @example 上传文件
+      # @example append a file
       #   append_object('x', 0, :file => '/tmp/x')
-      # @example 指定Content-Type和metas
+      # @example specifies Content-Type and metas
       #   append_object('x', 0, :file => '/tmp/x', :content_type => 'text/html',
       #                 :metas => {'year' => '2015', 'people' => 'mary'})
-      # @return [Integer] 返回下次append的位置
-      # @yield [HTTP::StreamWriter] 同 {#put_object}
+      # @return [Integer] return the offset for next append.
+      # @yield [HTTP::StreamWriter] same as {#put_object}
       def append_object(key, pos, opts = {}, &block)
         args = opts.dup
 
@@ -351,26 +340,24 @@ def append_object(key, pos, opts = {}, &block)
         next_pos
       end
 
-      # 将Bucket中的一个object拷贝成另外一个object
-      # @param source [String] 源object名字
-      # @param dest [String] 目标object名字
-      # @param opts [Hash] 拷贝object时的选项（可选）
-      # @option opts [String] :src_bucket 源object所属的Bucket，默认与
-      #  目标文件为同一个Bucket。源Bucket与目标Bucket必须属于同一个Region。
-      # @option opts [String] :acl 目标文件的acl属性，默认为private
-      # @option opts [String] :meta_directive 指定是否拷贝源object的
-      #  meta信息，默认为{OSS::MetaDirective::COPY}：即拷贝object的时
-      #  候也拷贝meta信息。
-      # @option opts [Hash] :metas 设置object的meta，这是一些用户自定
-      #  义的属性，它们会和object一起存储，在{#get_object}的时候会
-      #  返回这些meta。属性的key不区分大小写。例如：{ 'year' => '2015'
-      #  }。如果:meta_directive为{OSS::MetaDirective::COPY}，则:metas
-      #  会被忽略。
-      # @option opts [Hash] :condition 指定拷贝object需要满足的条件，
-      #  同 {#get_object}
-      # @return [Hash] 目标文件的信息
-      #  * :etag [String] 目标文件的ETag
-      #  * :last_modified [Time] 目标文件的最后修改时间
+      # copy an object in the bucket to another one.
+      # @param source [String] source object name
+      # @param dest [String] target object name
+      # @param opts [Hash] options 
+      # @option opts [String] :src_bucket source object's bucket. By default it's same as the target object's bucket
+      #  Source Bucket and target bucket must belong to the same region.
+      # @option opts [String] :acl target object's ACL property. Default is private.
+      # @option opts [String] :meta_directive specifies if copying the metadata from source object as well.
+      #  Default is {OSS::MetaDirective::COPY}：means it copies the metadata.
+      # @option opts [Hash] :metas Sets object's meta，which is stored with the object content.
+      #  {#get_object} could return these metadata.
+      #  Its key is case insensitive. For example: { 'year' => '2015'}. 
+      #  if meta_directive is {OSS::MetaDirective::COPY}, then this opt will be ignored.
+      # @option opts [Hash] :condition specifies conditions to copy the object.
+      #  It's same as {#get_object}.
+      # @return [Hash] target object's information.
+      #  * :etag [String] Target object's ETag
+      #  * :last_modified [Time] Target object last modified time.
       def copy_object(source, dest, opts = {})
         args = opts.dup
 
@@ -378,89 +365,80 @@ def copy_object(source, dest, opts = {})
         @protocol.copy_object(name, source, dest, args)
       end
 
-      # 删除一个object
-      # @param key [String] Object的名字
+      # Deletes an object
+      # @param key [String] Object name
       def delete_object(key)
         @protocol.delete_object(name, key)
       end
 
-      # 批量删除object
-      # @param keys [Array<String>] Object的名字集合
-      # @param opts [Hash] 删除object的选项（可选）
-      # @option opts [Boolean] :quiet 指定是否允许Server返回成功删除的
-      #  object，默认为false，即返回删除结果
-      # @return [Array<String>] 成功删除的object的名字，如果指定
-      #  了:quiet参数，则返回[]
+      # deletes multiple objects
+      # @param keys [Array<String>] Object names' set
+      # @param opts [Hash] options for deleting objects
+      # @option opts [Boolean] :quiet specifies if prevent server returning objects status. 
+      #  Default is false which means returns all the objects' deletion status.
+      # @return [Array<String>] return deleted objects list. If quiet is specified, return [].
       def batch_delete_objects(keys, opts = {})
         @protocol.batch_delete_objects(
           name, keys, opts.merge(encoding: KeyEncoding::URL))
       end
 
-      # 设置object的ACL
-      # @param key [String] Object的名字
-      # @param acl [String] Object的{OSS::ACL ACL}
+      # Sets object ACL
+      # @param key [String] Object name
+      # @param acl [String] Object's {OSS::ACL ACL}
       def set_object_acl(key, acl)
         @protocol.put_object_acl(name, key, acl)
       end
 
-      # 获取object的ACL
-      # @param key [String] Object的名字
+      # Gets object ACL
+      # @param key [String] Object name
       # @return [String] object的{OSS::ACL ACL}
       def get_object_acl(key)
         @protocol.get_object_acl(name, key)
       end
 
-      # 获取object的CORS规则
-      # @param key [String] Object的名字
+      # Gets object's CORS rule
+      # @param key [String] Object name
       # @return [OSS::CORSRule]
       def get_object_cors(key)
         @protocol.get_object_cors(name, key)
       end
 
       ##
-      # 断点续传相关的API
+      # APIs about upload with checkpoint (a.k. resumable upload)
       #
 
-      # 上传一个本地文件到bucket中的一个object，支持断点续传。指定的文
-      # 件会被分成多个分片进行上传，只有所有分片都上传成功整个文件才
-      # 上传成功。
-      # @param key [String] Object的名字
-      # @param file [String] 本地文件的路径
-      # @param opts [Hash] 上传文件的可选项
-      # @option opts [String] :content_type 设置所上传的内容的
-      #  Content-Type，默认是application/octet-stream
-      # @option opts [Hash] :metas 设置object的meta，这是一些用户自定
-      #  义的属性，它们会和object一起存储，在{#get_object}的时候会
-      #  返回这些meta。属性的key不区分大小写。例如：{ 'year' => '2015' }
-      # @option opts [Integer] :part_size 设置分片上传时每个分片的大小，
-      #  默认为10 MB。断点上传最多允许10000个分片，如果文件大于10000个
-      #  分片的大小，则每个分片的大小会大于10MB。
-      # @option opts [String] :cpt_file 断点续传的checkpoint文件，如果
-      #  指定的cpt文件不存在，则会在file所在目录创建一个默认的cpt文件，
-      #  命名方式为：file.cpt，其中file是用户要上传的文件。在上传的过
-      #  程中会不断更新此文件，成功完成上传后会删除此文件；如果指定的
-      #  cpt文件已存在，则从cpt文件中记录的点继续上传。
-      # @option opts [Boolean] :disable_cpt 是否禁用checkpoint功能，如
-      #  果设置为true，则在上传的过程中不会写checkpoint文件，这意味着
-      #  上传失败后不能断点续传，而只能重新上传整个文件。如果这个值为
-      #  true，则:cpt_file会被忽略。
-      # @option opts [Callback] :callback 指定文件上传成功后OSS的
-      #  上传回调，上传成功后OSS会向用户的应用服务器发一个HTTP POST请
-      #  求，`:callback`参数指定这个请求的相关参数
-      # @option opts [Hash] :headers 指定请求的HTTP Header，不区分大小
-      #  写。这里指定的值会覆盖通过`:content_type`和`:metas`设置的值。
-      # @yield [Float] 如果调用的时候传递了block，则会将上传进度交由
-      #  block处理，进度值是一个0-1之间的小数
-      # @raise [CheckpointBrokenError] 如果cpt文件被损坏，则抛出此错误
-      # @raise [FileInconsistentError] 如果指定的文件与cpt中记录的不一
-      #  致，则抛出此错误
-      # @raise [CallbackError] 如果文件上传成功而Callback调用失败，抛
-      #  出此错误
+      # Uploads a local file to the bucket with checkpoint support. 
+      # The file will be upload in parts and only after all parts upload succeed, the file upload is complete and available for access.
+      # 
+      # @param key [String] Object key
+      # @param file [String] the local file path
+      # @param opts [Hash] options for upload file
+      # @option opts [String] :content_type content-type
+      #  Content-Type，default is application/octet-stream
+      # @option opts [Hash] :metas Sets object meta which is user's custom attributes. They're stored with the object content.
+      #  The meta information is returned in {#get_object}'s response.
+      #  The keys in meta are case insensitive. For example：{ 'year' => '2015' }
+      # @option opts [Integer] :part_size Part size
+      #  Default is 10 MB. The max part count is 10,000.
+      # @option opts [String] :cpt_file the checkpoint file path (local) If the cpt_file does not exist, it will create a 
+      # default cpt file (named as $file.cpt, $file is the file name to upload) of the current file's folder.
+      # The cpt file has the upload progress information and thus if the upload failed, the next upload would resume 
+      # the upload according to the checkpoint.
+      # @option opts [Boolean] :disable_cpt flag of disabling checkpoint function. If true, the checkpoint function is disabled and cpt_file is ignored.
+      # @option opts [Callback] :callback specifies the callback information after a successful upload.
+      #  After the file is uploaded, OSS could send a POST request to the specified URL and other information in the callback parameter.
+      # @option opts [Hash] :headers specifies the HTTP headers in the request, it's case insensitive.
+      #  The values could overwrite the one set by `:content_type` and `:metas`.
+      # @yield [Float] If the block is specified, the upload progress will be stored in the block.
+      #  The progress is the number between 0 to 1.
+      # @raise [CheckpointBrokenError] If the cp file is corrupted, the CheckpointBrokenError is thrown.
+      # @raise [FileInconsistentErro] If the specified file does not match the one in cpt, the eFileInconsistentError is thrown.
+      # @raise [CallbackError] If the file is uploaded but the callback call fails, CallbackError is thrown
       # @example
       #   bucket.resumable_upload('my-object', '/tmp/x') do |p|
       #     puts "Progress: #{(p * 100).round(2)} %"
       #   end
-      # @example 指定Callback
+      # @example specifies Callback
       #   callback = Aliyun::OSS::Callback.new(
       #     url: 'http://10.101.168.94:1234/callback',
       #     query: {user: 'put_object'},
@@ -468,9 +446,8 @@ def get_object_cors(key)
       #   )
       #
       #   bucket.resumable_upload('files/hello', '/tmp/x', callback: callback)
-      # @note 如果指定了`:callback`，则可能文件上传成功，但是callback
-      #  执行失败，此时会抛出{OSS::CallbackError}，用户可以选择接住这
-      #  个异常，以忽略Callback调用错误
+      # @note If `:callback` is specified, then it's possible that file upload succeeds but callback fails.
+      #  Then in this case the {OSS::CallbackError} is thrown. User could opt to catch this exception to ignore the callback failure.
       def resumable_upload(key, file, opts = {}, &block)
         args = opts.dup
 
@@ -486,43 +463,27 @@ def resumable_upload(key, file, opts = {}, &block)
         ).run
       end
 
-      # 下载bucket中的一个object到本地文件，支持断点续传。指定的object
-      # 会被分成多个分片进行下载，只有所有的分片都下载成功整个object才
-      # 下载成功。对于每个下载的分片，会在file所在目录建立一个临时文件
-      # file.part.N，下载成功后这些part文件会被合并成最后的file然后删
-      # 除。
-      # @param key [String] Object的名字
-      # @param file [String] 本地文件的路径
-      # @param opts [Hash] 下载文件的可选项
-      # @option opts [Integer] :part_size 设置分片上传时每个分片的大小，
-      #  默认为10 MB。断点下载最多允许100个分片，如果文件大于100个分片，
-      #  则每个分片的大小会大于10 MB
-      # @option opts [String] :cpt_file 断点续传的checkpoint文件，如果
-      #  指定的cpt文件不存在，则会在file所在目录创建一个默认的cpt文件，
-      #  命名方式为：file.cpt，其中file是用户要下载的文件名。在下载的过
-      #  程中会不断更新此文件，成功完成下载后会删除此文件；如果指定的
-      #  cpt文件已存在，则从cpt文件中记录的点继续下载。
-      # @option opts [Boolean] :disable_cpt 是否禁用checkpoint功能，如
-      #  果设置为true，则在下载的过程中不会写checkpoint文件，这意味着
-      #  下载失败后不能断点续传，而只能重新下载整个文件。如果这个值为true，
-      #  则:cpt_file会被忽略。
-      # @option opts [Hash] :condition 指定下载object需要满足的条件，
-      #  同 {#get_object}
-      # @option opts [Hash] :headers 指定请求的HTTP Header，不区分大小
-      #  写。这里指定的值会覆盖通过`:condition`设置的值。
-      # @option opts [Hash] :rewrite 指定下载object时Server端返回的响
-      #  应头部字段的值，同 {#get_object}
-      # @yield [Float] 如果调用的时候传递了block，则会将下载进度交由
-      #  block处理，进度值是一个0-1之间的小数
-      # @raise [CheckpointBrokenError] 如果cpt文件被损坏，则抛出此错误
-      # @raise [ObjectInconsistentError] 如果指定的object的etag与cpt文
-      #  件中记录的不一致，则抛出错误
-      # @raise [PartMissingError] 如果已下载的部分(.part文件)找不到，
-      #  则抛出此错误
-      # @raise [PartInconsistentError] 如果已下载的部分(.part文件)的
-      #  MD5值与cpt文件记录的不一致，则抛出此错误
-      # @note 已经下载的部分会在file所在的目录创建.part文件，命名方式
-      #  为file.part.N
+      # Download bucket to the local file, with checkpoint supported. The specified object could be downloaded in parts.
+      # And only after all the parts are downloaded, the whole object download is complete.
+      # For every downloaded part, it will be stored in the file's folder with name pattern file.part.N.
+      # Once the download succceeds, all these parts will be merged to the final file and then get deleted.
+      # @param key [String] Object key
+      # @param file [String] the local file path
+      # @param opts [Hash] options for downloading the file.
+      # @option opts [Integer] :part_size part size. Default is 10MB. Max part count is 100 and thus the part size could be
+      # bigger if the file is more than 1GB.
+      # @option opts [String] :cpt_file checkpoint file. If the cpt file does not exist, it will create one named as $file.cpt----$file is the target file name.
+      #  If the cpt file exists, then the download will resume from the last download according to the checkpoint.
+      # @option opts [Boolean] :disable_cpt flag of disabling checkpoint. If true, then it's disabled and cpt_file is ignored.
+      # @option opts [Hash] :condition the conditions to download the object, same as {#get_object}.
+      # @option opts [Hash] :headers specifies the http headers (case insensitive). They may overwrite the values set by 'condition'.
+      # @option opts [Hash] :rewrite specifies the headers to ask OSS return them in the response. Check out {#get_object} for the detail.
+      # @yield [Float] If the block is specified, the download progress is stored in block, which is the number between 0 to 1.
+      # @raise [CheckpointBrokenError] If the cpt file is corrupted, the error is thrown.
+      # @raise [ObjectInconsistentError] If the object's ETag does not match the cpt file's one, the error is thrown.
+      # @raise [PartMissingError] If the download parts file do not exist, the error is thrown.
+      # @raise [PartInconsistentError] If the downloaded parts file's MD5 does not match with the CPT file, the error is thrown.
+      # @note The downloaded parts will be stored in the same folder of the target fiel with name as file.part.N.
       # @example
       #   bucket.resumable_download('my-object', '/tmp/x') do |p|
       #     puts "Progress: #{(p * 100).round(2)} %"
@@ -542,24 +503,15 @@ def resumable_download(key, file, opts = {}, &block)
         ).run
       end
 
-      # 列出此Bucket中正在进行的multipart上传请求，不包括已经完成或者
-      # 被取消的。
-      # @param [Hash] opts 可选项
-      # @option opts [String] :key_marker object key的标记，根据有没有
-      #  设置:id_marker，:key_marker的含义不同：
-      #  1. 如果未设置:id_marker，则只返回object key在:key_marker之后
-      #     （字典序，不包含marker）的upload请求
-      #  2. 如果设置了:id_marker，则返回object key在:key_marker之后
-      #     （字典序，不包含marker）的uplaod请求*和*Object
-      #     key与:key_marker相等，*且*upload id在:id_marker之后（字母
-      #     表顺序排序，不包含marker）的upload请求
-      # @option opts [String] :id_marker upload id的标记，如
-      #  果:key_marker没有设置，则此参数会被忽略；否则与:key_marker一起
-      #  决定返回的结果（见上）
-      # @option opts [String] :prefix 如果指定，则只返回object key中符
-      #  合指定前缀的upload请求
-      # @return [Enumerator<Multipart::Transaction>] 其中每一个元素表
-      #  示一个upload请求
+      # Lists all ongoing multipart upload requests, not includes completed or aborted one.
+      # @param [Hash] opts options
+      # @option opts [String] :key_marker object key marker. Its behavior depends on if id_marker is set:
+      #  1. If :id_marker is not specifeid，then returned objects' key are all larger than :key_marker in lexicrographic order.
+      #  2. If :id_marker is specified, then the returned objects' key are larger than :key_marker or same as the :key_marker but the upload id is 
+      #      bigger thant he :id_marker.
+      # @option opts [String] :id_marker upload id marker. See the detail in :key_marker.
+      # @option opts [String] :prefix if the prefix is specified, only return the uploads whose target object key has the specified prefix.
+      # @return [Enumerator<Multipart::Transaction>] Every element represents an upload request.
       # @example
       #   key_marker = 1, id_marker = null
       #   # return <2, 0>, <2, 1>, <3, 0> ...
@@ -570,26 +522,25 @@ def list_uploads(opts = {})
           @protocol, name, opts.merge(encoding: KeyEncoding::URL)).to_enum
       end
 
-      # 取消一个multipart上传请求，一般用于清除Bucket下因断点上传而产
-      # 生的文件碎片。成功取消后属于这个上传请求的分片都会被清除。
-      # @param [String] upload_id 上传请求的id，可通过{#list_uploads}
-      #  获得
-      # @param [String] key Object的名字
+      # Cancels the multipart upload request, to clear all parts data uploaded.
+      # A successful cancel will clear all uploaded parts data of the upload.
+      # @param [String] upload_id uplaod request Id. It could be retrieved from {#list_uploads}
+      # @param [String] key Object key.
       def abort_upload(upload_id, key)
         @protocol.abort_multipart_upload(name, key, upload_id)
       end
 
-      # 获取Bucket的URL
-      # @return [String] Bucket的URL
+      # Gets bucket's URL
+      # @return [String] Bucket URL
       def bucket_url
         @protocol.get_request_url(name)
       end
 
-      # 获取Object的URL
-      # @param [String] key Object的key
-      # @param [Boolean] sign 是否对URL进行签名，默认为是
-      # @param [Fixnum] expiry URL的有效时间，单位为秒，默认为60s
-      # @return [String] 用于直接访问Object的URL
+      # Gets object's URL
+      # @param [String] key Object key
+      # @param [Boolean] sign flag of signing the url. Default is true
+      # @param [Fixnum] expiry URL's expiration time in seconds. Default is 60 seconds.
+      # @return [String] return the object's URL which could be used for accessing the object directly.
       def object_url(key, sign = true, expiry = 60)
         url = @protocol.get_request_url(name, key)
         return url unless sign
@@ -626,15 +577,15 @@ def object_url(key, sign = true, expiry = 60)
         [url, query_string].join('?')
       end
 
-      # 获取用户所设置的ACCESS_KEY_ID
-      # @return [String] 用户的ACCESS_KEY_ID
+      # gets the user's ACCESS_KEY_ID
+      # @return [String] gets the user's ACCESS_KEY_ID
       def access_key_id
         @protocol.get_access_key_id
       end
 
-      # 用ACCESS_KEY_SECRET对内容进行签名
-      # @param [String] string_to_sign 要进行签名的内容
-      # @return [String] 生成的签名
+      # Sign the content with ACCESS_KEY_SECRET
+      # @param [String] string_to_sign the content to sign
+      # @return [String] the signature
       def sign(string_to_sign)
         @protocol.sign(string_to_sign)
       end
diff --git a/lib/aliyun/oss/client.rb b/lib/aliyun/oss/client.rb
index 59aaf26..89ca3a6 100644
--- a/lib/aliyun/oss/client.rb
+++ b/lib/aliyun/oss/client.rb
@@ -4,9 +4,9 @@ module Aliyun
   module OSS
 
     ##
-    # OSS服务的客户端，用于获取bucket列表，创建/删除bucket。Object相关
-    # 的操作请使用{OSS::Bucket}。
-    # @example 创建Client
+    # OSS service's client class, which is for getting bucket list, creating or deleting bucket. For {OSS:Object} related operations, 
+    # please use {OSS::Bucket}.
+    # @example creates a Client object
     #   endpoint = 'oss-cn-hangzhou.aliyuncs.com'
     #   client = Client.new(
     #     :endpoint => endpoint,
@@ -18,30 +18,24 @@ module OSS
     #   bucket = client.get_bucket('my-bucket')
     class Client
 
-      # 构造OSS client，用于操作buckets。
-      # @param opts [Hash] 构造Client时的参数选项
-      # @option opts [String] :endpoint [必填]OSS服务的地址，可以是以
-      #  oss-cn-hangzhou.aliyuncs.com的标准域名，也可以是用户绑定的域名
-      # @option opts [String] :access_key_id [可选]用户的ACCESS KEY ID，
-      #  如果不填则会尝试匿名访问
-      # @option opts [String] :access_key_secret [可选]用户的ACCESS
-      #  KEY SECRET，如果不填则会尝试匿名访问
-      # @option opts [Boolean] :cname [可选] 指定endpoint是否是用户绑
-      #  定的域名
-      # @option opts [Boolean] :upload_crc_enable [可选]指定上传处理
-      #  是否开启CRC校验，默认为开启(true)
-      # @option opts [Boolean] :download_crc_enable [可选]指定下载处理
-      #  是否开启CRC校验，默认为不开启(false)
-      # @option opts [String] :sts_token [可选] 指定STS的
-      #  SecurityToken，如果指定，则使用STS授权访问
-      # @option opts [Fixnum] :open_timeout [可选] 指定建立连接的超时
-      #  时间，默认为10秒
-      # @option opts [Fixnum] :read_timeout [可选] 指定等待响应的超时
-      #  时间，默认为120秒
-      # @example 标准endpoint
+      # creates OSS client for buckets operations.
+      # @param opts [Hash] options for creating the Client object
+      # @option opts [String] :endpoint [required] OSS endpoint. It could be standard endpoint such as
+      #  oss-cn-hangzhou.aliyuncs.com or user domain binded with the bucket
+      # @option opts [String] :access_key_id [optional] user's ACCESS KEY ID，
+      #  if not specified, then the request is anonymous.
+      # @option opts [String] :access_key_secret [optional] user's ACCESS
+      #  KEY SECRET，if not specified, then the request is anonymous.
+      # @option opts [Boolean] :cname [optional] flag indicates if the endpoint is CNamed.
+      # @option opts [Boolean] :upload_crc_enable [optional] specifies if the upload enabled with CRC. Default is true.
+      # @option opts [Boolean] :download_crc_enable [optional] specifies if the download enabled with CRC. Default is false.
+      # @option opts [String] :sts_token [optional] specifies STS's SecurityToken. If it's specified, then use STS for authorization.
+      # @option opts [Fixnum] :open_timeout [optional] the connection timeout in seconds. By default it's 10s.
+      # @option opts [Fixnum] :read_timeout [optional] the response's timeout in seconds. By default it's 120s.
+      # @example standard endpoint
       #   oss-cn-hangzhou.aliyuncs.com
       #   oss-cn-beijing.aliyuncs.com
-      # @example 用户绑定的域名
+      # @example cname binded endpoint
       #   my-domain.com
       #   foo.bar.com
       def initialize(opts)
@@ -51,12 +45,11 @@ def initialize(opts)
         @protocol = Protocol.new(@config)
       end
 
-      # 列出当前所有的bucket
-      # @param opts [Hash] 查询选项
-      # @option opts [String] :prefix 如果设置，则只返回以它为前缀的bucket
-      # @option opts [String] :marker 如果设置，则只返回名字在它之后
-      #  （字典序，不包含marker）的bucket
-      # @return [Enumerator<Bucket>] Bucket的迭代器
+      # Lists all buckets of the account
+      # @param opts [Hash] options for the list
+      # @option opts [String] :prefix if it's specified, only buckets prefixed with it will be returned
+      # @option opts [String] :marker if it's specified, only buckets whose key is larger than :marker will be returned.
+      # @return [Enumerator<Bucket>] Bucket's iterator
       def list_buckets(opts = {})
         if @config.cname
           fail ClientError, "Cannot list buckets for a CNAME endpoint."
@@ -65,24 +58,24 @@ def list_buckets(opts = {})
         Iterator::Buckets.new(@protocol, opts).to_enum
       end
 
-      # 创建一个bucket
-      # @param name [String] Bucket名字
-      # @param opts [Hash] 创建Bucket的属性（可选）
-      # @option opts [:location] [String] 指定bucket所在的区域，默认为oss-cn-hangzhou
+      # Creates a bucket
+      # @param name [String] Bucket name
+      # @param opts [Hash] options for creating the bucket（optional）
+      # @option opts [:location] [String] the region for the new bucket. By default is oss-cn-hangzhou
       def create_bucket(name, opts = {})
         @protocol.create_bucket(name, opts)
       end
 
-      # 删除一个bucket
-      # @param name [String] Bucket名字
-      # @note 如果要删除的Bucket不为空（包含有object），则删除会失败
+      # Deletes a bucket
+      # @param name [String] Bucket name
+      # @note If the bucket is not empty (has objects), then the deletion will fail.
       def delete_bucket(name)
         @protocol.delete_bucket(name)
       end
 
-      # 判断一个bucket是否存在
-      # @param name [String] Bucket名字
-      # @return [Boolean] 如果Bucket存在则返回true，否则返回false
+      # Checks if the bucket exists
+      # @param name [String] Bucket name
+      # @return [Boolean] If Bucket exists returns true; otherwise returns false.
       def bucket_exists?(name)
         exist = false
 
@@ -98,9 +91,9 @@ def bucket_exists?(name)
 
       alias :bucket_exist? :bucket_exists?
 
-      # 获取一个Bucket对象，用于操作bucket中的objects。
-      # @param name [String] Bucket名字
-      # @return [Bucket] Bucket对象
+      # Gets the bucket object for objects level operations
+      # @param name [String] Bucket name
+      # @return [Bucket] Bucket object
       def get_bucket(name)
         Bucket.new({:name => name}, @protocol)
       end
diff --git a/lib/aliyun/oss/object.rb b/lib/aliyun/oss/object.rb
index fe52ba0..e07c174 100644
--- a/lib/aliyun/oss/object.rb
+++ b/lib/aliyun/oss/object.rb
@@ -4,7 +4,7 @@ module Aliyun
   module OSS
 
     ##
-    # Object表示OSS存储的一个对象
+    # Object represents an object in OSS
     #
     class Object < Common::Struct::Base
 
diff --git a/lib/aliyun/sts/client.rb b/lib/aliyun/sts/client.rb
index f263e94..7192331 100644
--- a/lib/aliyun/sts/client.rb
+++ b/lib/aliyun/sts/client.rb
@@ -3,8 +3,8 @@
 module Aliyun
   module STS
 
-    # STS服务的客户端，用于向STS申请临时token。
-    # @example 创建Client
+    # The client for STS service, for requesting temporary token.
+    # @example creates Client
     #   client = Client.new(
     #     :access_key_id => 'access_key_id',
     #     :access_key_secret => 'access_key_secret')
diff --git a/rails/aliyun_oss_callback_server.rb b/rails/aliyun_oss_callback_server.rb
index e134fab..e8736ca 100644
--- a/rails/aliyun_oss_callback_server.rb
+++ b/rails/aliyun_oss_callback_server.rb
@@ -7,8 +7,8 @@
 require 'openssl'
 require 'json'
 
-# 接受OSS上传回调的server示例，利用RSA公钥验证请求来自OSS，而非其
-# 他恶意请求。具体签名/验证过程请参考：
+# Examples of callback server for OSS callback calls. It checks the request signature by using the public key of OSS.
+# Checks out the following link for exact process of signing/verification:
 # https://help.aliyun.com/document_detail/oss/api-reference/object/Callback.html
 
 def get_header(name)
diff --git a/spec/aliyun/oss/service_spec.rb b/spec/aliyun/oss/service_spec.rb
index ce2c557..4302dcc 100644
--- a/spec/aliyun/oss/service_spec.rb
+++ b/spec/aliyun/oss/service_spec.rb
@@ -24,7 +24,7 @@ module OSS
         end
       end
 
-      # 生成list_buckets返回的响应，包含bucket列表和more信息
+      # Generates the response of list_buckets, which contains the bucket list and more information.
       def mock_response(buckets, more)
         builder = Nokogiri::XML::Builder.new do |xml|
           xml.ListAllMyBucketsResult {
@@ -56,7 +56,7 @@ def mock_response(buckets, more)
       end
 
       context "List all buckets" do
-        # 测试list_buckets正确地发送了HTTP请求
+        # tests list_buckets send HTTP request correctly
         it "should send correct request" do
           stub_request(:get, @endpoint)
 
@@ -66,7 +66,7 @@ def mock_response(buckets, more)
                               with(:body => nil, :query => {})
         end
 
-        # 测试list_buckets正确地解析了list_buckets的返回
+        # tests list_buckets parse the response correctly.
         it "should correctly parse response" do
           stub_request(:get, @endpoint).to_return(
             {:body => mock_response(@all_buckets, {})})
@@ -82,7 +82,7 @@ def mock_response(buckets, more)
       end
 
       context "Paging buckets" do
-        # 测试list_buckets的请求中包含prefix/marker/maxkeys等信息
+        # tests list_buckets request has the information like prefix/marker/maskeys 
         it "should set prefix/max-keys param" do
           prefix = 'rubysdk-bucket-00'
           marker = 'rubysdk-bucket-002'
@@ -101,7 +101,7 @@ def mock_response(buckets, more)
                             'max-keys' => limit})
         end
 
-        # 测试list_buckets正确地解析了HTTP响应，包含more信息
+        # test list_buckets parse the response correctly, which has the more information.
         it "should parse next marker" do
           prefix = 'rubysdk-bucket-00'
           marker = 'rubysdk-bucket-002'
diff --git a/spec/aliyun/oss/util_spec.rb b/spec/aliyun/oss/util_spec.rb
index d27b498..514a045 100644
--- a/spec/aliyun/oss/util_spec.rb
+++ b/spec/aliyun/oss/util_spec.rb
@@ -6,7 +6,7 @@ module Aliyun
   module OSS
 
     describe Util do
-      # 测试对body content的md5编码是否正确
+      # test if the MD5 of the body content is correct.
       it "should get correct content md5" do
         content = ""
 
@@ -18,7 +18,7 @@ module OSS
         expect(md5).to eq("XrY7u+Ae7tCTyyK7j1rNww==")
       end
 
-      # 测试签名是否正确
+      # test if the signature is correct.
       it "should get correct signature" do
         key = 'helloworld'
         date = 'Fri, 30 Oct 2015 07:21:00 GMT'
@@ -44,7 +44,7 @@ module OSS
         expect(signature).to eq("7Oh2wobzeg6dw/cWYbF/2m6s6qc=")
       end
 
-      # 测试CRC计算是否正确
+      # test if the CRC calculation is correct.
       it "should calculate a correct data crc" do
         content = ""
         crc = Util.crc(content)
@@ -59,7 +59,7 @@ module OSS
         expect(crc).to eq(6745424696046691431)
       end
 
-      # 测试CRC Combine计算是否正确
+      # Test CRC combine calculation is correct or not.
       it "should calculate a correct crc that crc_a combine with crc_b" do
         content_a = "test\0hello\1world\2!\3"
         crc_a = Util.crc(content_a)
@@ -79,7 +79,7 @@ module OSS
         expect(crc_ab).to eq(crc_c)
       end
 
-      # 测试CRC校验和异常处理是否正确
+      # test CRC checksum and exception handler is correct or not.
       it "should check inconsistent crc" do
         expect {
           Util.crc_check(6745424696046691431, 6745424696046691431, 'put')