diff --git a/Changes b/Changes
index 00a7827..ff32783 100644
--- a/Changes
+++ b/Changes
@@ -1,5 +1,13 @@
 Revision history for Perl extension Lingua::JA::WebIDF
 
+0.40    Wed, 03 Oct 2012 12:57:56 +0900
+        - improved tests
+        - changed default options
+        - added verbose option
+        - removed Lingua::JA::WebIDF::API::Bing
+        - removed dependency on File::Sharedir
+        - removed dependency on JSON
+
 0.32    Sat, 28 Jul 2012 17:50:26 +0900
         - removed _plugin_list function
 
diff --git a/README b/README
index cc679eb..66a8bd7 100644
--- a/README
+++ b/README
@@ -4,7 +4,7 @@ NAME
 SYNOPSIS
       use Lingua::JA::WebIDF;
 
-      my $webidf = Lingua::JA::WebIDF->new;
+      my $webidf = Lingua::JA::WebIDF->new(%config);
 
       print $webidf->idf("東京"); # low
       print $webidf->idf("スリジャヤワルダナプラコッテ"); # high
@@ -12,9 +12,9 @@ SYNOPSIS
 DESCRIPTION
     Lingua::JA::WebIDF calculates WebIDF weight.
 
-    WebIDF(Inverse Document Frequency) weight represents the rarity of words
-    on the Web. The WebIDF weight of rare words is high. Conversely, the
-    WebIDF weight of common words is low.
+    WebIDF(Inverse Document Frequency) weight represents the rarity of a
+    word on the Web. The WebIDF weight of a rare word is high. Conversely,
+    the WebIDF weight of a common word is low.
 
     IDF is based on the intuition that a query term which occurs in many
     documents is not a good discriminator and should be given less weight
@@ -80,8 +80,8 @@ METHODS
     fech_df => 0
         Never fetches WebDF from the Web if 0 is specified.
 
-        If the WebDF you want to know is already saved, it is used. If not
-        so, returns undef.
+        If the WebDF you want to know has already saved, it is used. If it
+        is not so, returns undef.
 
     expires_in => $days
         If 365 is specified, WebDF expires in 365 days after fetches it.
@@ -103,8 +103,8 @@ METHODS
     If the WebDF of $word has not been saved yet or has expired, fetches it
     by using the Web API you specified and saves it.
 
-    If the WebDF of $word expires and fetch_df is 0, the expiring WebDF of
-    $word is used.
+    If the WebDF of $word has expired and fetch_df is 0, the expired WebDF
+    is used.
 
   db_open($mode)
     Opens the database file which is located in $path.
diff --git a/lib/Lingua/JA/WebIDF.pm b/lib/Lingua/JA/WebIDF.pm
index 6d5abb9..632a9e8 100644
--- a/lib/Lingua/JA/WebIDF.pm
+++ b/lib/Lingua/JA/WebIDF.pm
@@ -8,7 +8,7 @@ use Carp ();
 use Module::Load ();
 use Furl::HTTP;
 
-our $VERSION = '0.32';
+our $VERSION = '0.40';
 
 
 sub _options
@@ -218,13 +218,13 @@ __END__
 Lingua::JA::WebIDF - WebIDF calculator
 
 =for test_synopsis
-my ($appid);
+my (%config);
 
 =head1 SYNOPSIS
 
   use Lingua::JA::WebIDF;
 
-  my $webidf = Lingua::JA::WebIDF->new;
+  my $webidf = Lingua::JA::WebIDF->new(%config);
 
   print $webidf->idf("東京"); # low
   print $webidf->idf("スリジャヤワルダナプラコッテ"); # high
@@ -233,9 +233,9 @@ my ($appid);
 
 Lingua::JA::WebIDF calculates WebIDF weight.
 
-WebIDF(Inverse Document Frequency) weight represents the rarity of words on the Web.
-The WebIDF weight of rare words is high.
-Conversely, the WebIDF weight of common words is low.
+WebIDF(Inverse Document Frequency) weight represents the rarity of a word on the Web.
+The WebIDF weight of a rare word is high.
+Conversely, the WebIDF weight of a common word is low.
 
 IDF is based on the intuition that a query term which occurs in
 many documents is not a good discriminator and should be given less weight
@@ -312,8 +312,8 @@ you specifies because WebDF may be different depending on it.
 
 Never fetches WebDF from the Web if 0 is specified.
 
-If the WebDF you want to know is already saved, it is used.
-If not so, returns undef.
+If the WebDF you want to know has already saved, it is used.
+If it is not so, returns undef.
 
 =item expires_in => $days
 
@@ -342,8 +342,8 @@ Fetches the WebDF of $word.
 If the WebDF of $word has not been saved yet or has expired,
 fetches it by using the Web API you specified and saves it.
 
-If the WebDF of $word expires and fetch_df is 0,
-the expiring WebDF of $word is used.
+If the WebDF of $word has expired and fetch_df is 0,
+the expired WebDF is used.
 
 =head2 db_open($mode)