在複合句中，修飾某一名詞或代詞的從句叫做定語從句。
知識梳理：提綱挈領，抓住重點和難點！
定語從句所修飾的詞 叫先行詞。 定語從句放在先行詞後面。定語從句分爲限定性定語從句和非限定性定語從句。本章只介紹限定性定語從句。引導定語從句的詞有關係代詞that、which、who、 which、 whose和關係副詞where 、when，關係代詞和關係副詞是引導詞， 在定語從句中擔當某一成份。
關係代詞和關係副詞的作用：
先行詞指物時， 關係代詞用that 或which（在句中作主語或賓語）。
如：China is a country which / that has a large population.
The computer game which/ that he is playing is his favorite.
先行詞指人時， 關係代詞用（who）作主語或賓語，whom (作賓語)，whose (作定語)，that (作主語或賓語)。 如：
The man who is mending the machine has been retired.
This is the policeman who/ whom they were talking about yesterday.
I like the girl whose mother is an actor.
注意：下列情況下關係代詞只用that 而不用which 或 who。
先行詞是指物的不代詞，如：all, little, few, much, none, anything, nothing, everything等時。如：I didn‘t understand the words all that he said.
2．先行詞由最高級、序數詞以及any, very, only, all, no, just 等所修飾。如：This is the most beautiful place that I have been to .
行詞既包括人，也包括物。如：They always like to talk about the man and the things that they see on the road.
當主句是以which 或who 開頭的.特殊疑問句時。如：who is the man that opened up the lab.
例題解析：舉一反三，學的更輕鬆！
He is a friend ______ can help you in time of need.
A. who he B. whose C. / D. who
解析：引導詞在定語從句中做主語，指人。 應選D 。
The most important thing ______ we should pay attention to is the first thing ______ I have said.
A. which, that B. that, which C. which, which D. that, that
解析：先行詞前有序數詞， 最高級時，引導次只能用 that. 應選D.
This is the only one of these books that ______worth reading.
A．has B. have C. is D. are
解析：引導詞that在句中作主語，代指one ，應選C。
The man ______ talked to you just now is my father.
A. who B. he C. which D. whose
解析：引導詞在句中作主語指人，應選A.
They thought too much about ______.
A. which I had said B. what I had said
C. that I had said D. I had said
解析：此題引導詞作在從句中作賓語，表示說話的內容，應 選B。
練習與鞏固：熟能生巧，取得好成績！
一、選擇最佳答案填空：
1．Did you find the notebook ______ Jim had given me for my birthday?
A. who B. whom C. which D. whose
2. That‘s all ______ I have seen and heard.
A. which B. that C. where D. what
3. Have you seen the man ______ plan we were talking about ______ yesterday ?
A. who, them B. its, them C. whose,/ D. whose, them
Oscar is one of the film prizes ______ offered to any Chinese actor or actress so far.
A. which are not B. that have not been C. that has not D. that has not been
5. He never reads anything ______ is not worth reading.
A. that B. as C. who D. which
6. The man ________ coat is black is waiting at the gate.
A. who‘s B. whose C. that D. of which
7. _________ cleans the classroom can go home first.
A. Anyone B. those whoo C. However D. The one who
8. The police caught the man _______ stole my handbag.
A. he B. that C. whom D. which
9. The girl ________ is reading under the tree ________ my sister.
A. which, is B. whom, was C. who , is D. who, was
10. George Mallory was an English teacher _______ loved climbing.
A. who B. whom C. he D. which
1-5 CDCBA 6-10 BDBCA
