命令，是否应该改为 关键字

[qinhanlei]

建议使用关键字这个更合适的术语，如 TypeScript 官网文档所示：

Variable Declarations

Declaring a variable in JavaScript has always traditionally been done with the var keyword.

By now you’ve figured out that var has some problems, which is precisely why let statements were introduced. Apart from the keyword used, let statements are written the same way var statements are.

[ruanyf]

关键字分成不同用途，有的是命令（delete），有的是语言结构（比如if），我想区分这两者。