1. 定义：在复合句中修饰某一名词或代词的从句叫做定语从句。
2. 先行词：被定语从句所修饰的词 (名词或代词) 叫先行词。 定语从句放在先行词的后边。
3. 定语从句由于关系代词和关系副词引导，关系代词或关系副词放在先行词和定语从句之间，起联系作用，同时又作从句中的一个成分。
| 关系代词 | 在句子中的作用 | 指代作用 | | that | 主语、宾语或表语 | 指人或指物 | | who | 主语、宾语或表语 | 指人（可与that互换） | | whom | 宾语（动宾或介宾） | 指人 | | whose | 定语 | 指人或指物 | | which | 主语或宾语 | 指物（有时可与that互换） |
1. who指人,作主语或宾语 (作宾语可省略）
The man who I talked with is our teacher.
A person who steals things is called a thief.
2. whom指人,作宾语 (作宾语可省略,如介词提前则不能省)
The man (whom/who) I nodded to is Mr. Li.
The man to whom I nodded is Professor Li.
3. which 指物，作主语或宾语 (作宾语可省略, 如介词提前则不能省)
These are the trees which were planted last year.
This recorder (which) he is using is made in Japan.
Is this the library (which) you borrow books from?
Is this the library from which you borrow books?
4. that 指人/物，作主语或宾语 (作宾语可省略）
A plane is a machine. It can fly.
A plane is a machine that can fly.
He is the man. I told you about him.
He is the man (that) I told you about.
5. whose 作定语
I know the girl whose mother is a famous doctor.
在选择引导定语从句的关系代词时，有如下要点：
1 由于关系代词在主句与从句间既起到联系作用，又在从句中充当一个成分，因此， 要正确判断关系代词在从句中的功能，如作主语还是宾语等。
2 当先行词指人时，关系代词可用who（做主语，宾语），that（做主语，宾语），whom（作宾语），whose（作定语）
3 当先行词指物时，关系代词可用that（做主语，宾语），which（做主语，宾语）
4 再定语从句中，作宾语的关系代词长可省略，但在介词后面的关系代词不能省略。指人时，介词后只用whom，指物时，介词后只用which。
5 在非限制性定语从句中，指人时，只用who，指物时，只用which。
小练习：
(1) The scientist is very famous in the world. We met her yesterday.
The scientist Ø we met yesterday is very famous in the world.
who
whom
that
(2) The dress is new. She is wearing it.
The dress that she is wearing is new.
which
Ø
(3) He is the kind person. I have ever worked with him.
He is the kind person that I have ever worked with.
who
whom
Ø
(4) This is the best film. I have ever seen this film.
This is the best film that I have ever seen.
Ø
| 关系副词 | 在句子中的作用 | 指代作用 | | when(on / in /during which) | 时间状语 | 指代时间名词 | | where(in / at which) | 地点状语 | 指代地点名称 | | why( for which) | 原因状语 | 指代原因 |
1. when 在从句中作时间状语
I’ll never forget the day when we met for the first time.
The story happened on the day when he was born.
2. Where 在从句中作地点状语
This is the place where I lived 5 years ago.
He showed me the building where his father worked.
3. Why 在从句中作原因状语
I don’t know the reason why he is always late for school.
This is the reason why we must go earlier.
在定语从句中，只用 that 不用 which 的情况
1〉当先行词前有序数词，形容词最高级，或限定词：the only，the same，the last, the very 等修饰时，只用that，不用 which
1.This is my first trip _____I have made in my life.
2.The most beautiful place ______he has visited is Guilin.
3.This is the only gift _____I have got from him.
4. It is the very pen _____ I am looking for.
5. The last place _____they visited in China was Mount Hua.
6. This is the very book ______ belongs to him.
2〉当先行词为不定代词时，如：anything， all，no， some， every，everything， nothing， none，much， little等词时，只用that，不用which
1. She took away everything _________belongs to her.
2.You can borrow any book ________ you want to read.
3.I’m sure she has something _______ you can borrow.
4. I’ve read all the books_______ I borrowed from Betty.
3〉当有两个以上的先行词，且先行词中有人也有物时，只用that， 不用which。
The old man talked about the persons and things ______he could remember.
The writer and his novel _____ you talked about just now are really well known.
4〉当主句以who 或which 开头时, 只用that,不用which：
Who is the girl _____spoke to you just now?
Which is the car _______was made in China?
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