定语从句中why的用法

引导语：定语从句中why的用法是怎样？下面由小编告诉你们吧，欢迎阅读！

定语从句中why的用法

请分析下面两个简单句：

句①He wanted to know the reason.

句②I was late for the reason.

把句②变为句①的定语从句，句①中的 reasons做定语从句的先行词。因为the reason做介词for的宾语，先行词是the reason指物，在定语从句中介词for提前，用关系代词which替代the reason，the reason就不能在定语从句中出现了。由此得到句③He wanted to know the reason for which I was late.

注意：在定语从句中当先行词为the reason(s)，定语从句由for which引导时，可以用why代替for which。由此我们得到句⑤He wanted to know the reason why I was late.

请把下面两句话合并为一句，把第二句话变为第一句的定语从句。

The reason is not very convincing.

He came for the reason.

→The reason why he came is not very convincing.

The reason for which he came is not very convincing.

　　定语从句

定语从句，一个简单句跟在一名词或代词后（先行词）进行修饰限定，就叫做定语从句。在主句中充当定语成分。被修饰的词叫先行词。定语从句不同于单词作定语的情况，它通常只能放在被修饰的词（即先行词）之后。

定语 从句由关系词（关系代词、关系副词）引导，关系代词、关系副词位于定语从句句首。