例如： 1) The man who lives next to us is a fool.
2) You must buy me the house which is near Xiangshan.
上面兩句中的the man和the house是定語從句所修飾的詞，叫先行詞，定語從句放在先行詞的後面。
二、關係詞(連線詞)
1.關係代詞引導的定語從句
引導定語從句的.關係詞有關係代詞：that, which, who 和關係副詞where, when, why。關係詞放在先行詞和定語從句之間，起連線作用，同時還做定語從句的一個成分。
2.關於that, which的用法注意點
1)只能用that，不用which作為定語從句關係代詞的情況
a)不定代詞，如anything, nothing, the one, all, much, few, any, little等作先行詞
There is nothing that I can do.
I mean the one that was bought yesterday.
b)先行詞有the only, the very, the same, the last修飾
This is the very book that I want to find.
The last place that I visited was the hospital.
c)先行詞為序數詞、數詞、形容詞最高階時
This is the first composition that he has written in English.
d)先行詞既有人，又有物時
He talked about the teachers and schools that he had visited.
