摘要：定语从句如同句子里的修饰大师，用于修饰名词或代词，在句中作定语。被修饰的词叫先行词，从句常紧跟其后。

定语从句如同句子里的修饰大师，用于修饰名词或代词，在句中作定语。被修饰的词叫先行词，从句常紧跟其后。

The boy who is standing there is my brother.

The boy 是先行词，who is standing there就是修饰它的定语从句。

关系词是定语从句的关键，分关系代词和关系副词。

①关系代词

who指人，作主语。

The man who saved the girl is a hero.

whom：指人，作宾语，口语中常省略。

The teacher (whom) we met yesterday is kind.

which指物，作主或宾语。

The book which lies on the table is mine.

that：可指人或物，作主或宾语。但先行词被最高级、序数词、不定代词修饰，或被the only等词修饰时，只能用that。

whose表所属，指人或物，作定语。

The boy whose father is a doctor studies hard.

② 关系副词

when指时间，作时间状语，先行词多为时间名词，

I remember the day when I came to this school.

where指地点，作地点状语，先行词是地点名词

This is the house where I lived.

why指原因，作原因状语，先行词只有reason。

The reason why he was late was that he missed the bus.

③ 定语一定知道的要点

主谓一致：从句谓语与先行词在人称和数上一致。

I, who am your friend, will help you.

as引导的定语从句：引导限制性定语从句，与such、the same搭配；引导非限制性定语从句，可放句首、中、末，指代主句内容。

As we know, he is a good student.

来源：擎苍教育