状语从句
定义
一个句子等于是一个副词
副词：修饰动词（整个句子也归为此类，因为句子核心是动词）、形容词、介词
因此状语从句也只有这三个功能
规则
只有一个关系连词引导
If/when/where/although/though/while/because/as(= when/while/because)
修饰动词
If 分句, 主语 谓语 宾语
If 分句 修饰 谓语
I can beat you, if you are happy. = If you are happy, I can beat you.
I like this game played by him when he is happy. 没有逗号时，状语从句修饰的动词遵循就近原则，因此修饰非谓语动词 played
I like this game played by him, when I am happy. 有逗号且根据句意，状语从句修饰主句动词：like
修饰形容词
There is a book useful and important for me when I am learning sth..