英语定语从句详解
掌握定语从句的构成、关系代词用法和分类规则
定语从句概述
什么是定语从句？
定语从句(Relative Clause)是一种形容词性从句，在复合句中修饰名词或代词，相当于形容词的作用，用来提供关于被修饰词的更多信息。
定语从句不能独立成句，必须依附于一个主句中的名词或代词（称为先行词），并通过关系代词或关系副词与先行词连接。
定语从句的核心要素
1. 先行词 (Antecedent)
The book that I read is interesting.
被定语从句修饰的名词或代词
2. 关系词 (Relative Word)
The book that I read is interesting.
连接主句和定语从句的词，同时在从句中充当一定成分
3. 定语从句本身
The book that I read is interesting.
包含完整主谓结构，修饰先行词的从句部分
定语从句的作用与特点
提供额外信息
补充说明先行词的特征、性质或状态
关系词的双重作用
既连接主句和从句，又在从句中充当主语、宾语等成分
位置固定
通常紧跟在先行词之后，不能随意放置
有限制和非限制之分
限制性定语从句与先行词关系密切，非限制性则为补充说明
定语从句 vs 形容词
用形容词修饰
a red car
an interesting book
用定语从句修饰
a car that is red
a book that interests me
关系代词和关系副词
关系词(Relative Words)是连接先行词和定语从句的桥梁，同时在从句中充当一定的句子成分。主要分为关系代词和关系副词两类：
关系代词 (Relative Pronouns)
who
指人在从句中作主语或宾语，指人
The man who is standing there is my teacher.（作主语）
The girl who we met yesterday is his sister.（作宾语）
whom
指人在从句中作宾语，指人，较正式，口语中常用who代替
The boy whom you helped is my brother.（作宾语）
* 在限制性定语从句中作宾语时可省略
which
指物在从句中作主语或宾语，指物
The book which lies on the desk is mine.（作主语）
The car which he bought is new.（作宾语）
that
指人/物在从句中作主语或宾语，既可指人也可指物
The girl that sits next to me is my friend.（指人，作主语）
The pen that I lost was expensive.（指物，作宾语）
whose
指所有格在从句中作定语，表示所属关系，既可指人也可指物
The man whose son is a doctor lives here.（指人）
The house whose windows are broken is empty.（指物）
关系副词 (Relative Adverbs)
when
指时间在从句中作时间状语，相当于"介词+which"
I remember the day when we first met.（= on which）
Do you know the year when he was born?（= in which）
where
指地点在从句中作地点状语，相当于"介词+which"
This is the school where I studied.（= in which）
He showed me the house where he lived.（= in which）
why
指原因在从句中作原因状语，相当于"for which"，通常修饰reason
Do you know the reason why he was late?（= for which）
The reason why she cried is unknown.（= for which）
that与which的使用区别
以下情况通常用that而不用which：
-
先行词是不定代词all, something, nothing等
I will tell you all that I know.
-
先行词被形容词最高级修饰
This is the best film that I have seen.
-
先行词被序数词修饰
The first thing that we should do is to work hard.
-
先行词既有人又有物
I remember the people and places that I visited.
定语从句的类型
限制性定语从句 (Restrictive Clauses)
限制性定语从句与先行词关系密切，是先行词不可缺少的部分，用来明确先行词的范围或特征，如果去掉会影响句子的意思。
主要特征
- • 没有逗号与主句隔开
- • 是先行词不可缺少的部分
- • 关系代词在从句中作宾语时可省略
例句
The students who study hard will pass the exam.
（修饰students，明确是"努力学习的学生"）
I have a book that you might like.
（修饰book，that在从句中作宾语，可省略）
This is the place where we met.
（修饰place，明确是"我们相遇的地方"）
非限制性定语从句 (Non-restrictive Clauses)
非限制性定语从句是对先行词的补充说明，去掉后不会影响句子的基本意思。通常修饰专有名词或已被限定的普通名词。
主要特征
- • 有逗号与主句隔开
- • 是先行词的补充说明，不是必需的
- • 关系代词不能省略，且不能用that
- • 可以修饰整个主句
例句
My brother, who lives in Beijing, is a doctor.
（补充说明brother的情况，有逗号隔开）
We visited Paris, which is a beautiful city.
（补充说明Paris，不能用that）
He passed the exam, which surprised us all.
（修饰整个主句，说明"他通过考试"这件事）
限制性与非限制性定语从句对比
| 特征 | 限制性定语从句 | 非限制性定语从句 |
|---|---|---|
| 标点符号 | 无逗号 | 有逗号隔开 |
| 与先行词关系 | 关系密切，不可缺少 | 补充说明，可有可无 |
| 关系代词that | 可以使用 | 不能使用 |
| 关系代词省略 | 作宾语时可省略 | 不能省略 |
| 修饰对象 | 通常修饰普通名词 | 可修饰专有名词或整个句子 |
| 例句 | The girl who sits here is my friend. | Mary, who sits here, is my friend. |
定语从句的规则与注意事项
关系代词的省略规则
可以省略的情况
在限制性定语从句中，关系代词作宾语时可以省略：
The book (that/which) I bought is interesting.
The man (who/whom) you met is my boss.
不能省略的情况
- 关系代词作主语时：
- The girl who is standing there is my sister.（不能省略who）
- 在非限制性定语从句中：
- My brother, who lives in Shanghai, is a teacher.（不能省略who）
- 关系代词是whose时：
- The boy whose father is a doctor is my friend.（不能省略whose）
常见错误与注意事项
1. 重复使用代词
关系代词已在从句中充当成分，不可再用其他代词重复指代先行词
× I know the man who he is a teacher.
√ I know the man who is a teacher.
2. 介词位置错误
当关系代词作介词宾语时，介词可放在关系代词前或句末
This is the book which I told you about.
This is the book about which I told you.
× This is the book about that I told you.
3. 混淆关系代词和关系副词
根据在从句中充当的成分选择关系词，作状语用副词，作主语/宾语用代词
× This is the place which I was born.
√ This is the place where I was born.
× I remember the day when we spent together.
√ I remember the day that we spent together.
4. 非限制性定语从句中使用that
非限制性定语从句中不能使用that，只能用who/which等
× My sister, that lives in Beijing, is a doctor.
√ My sister, who lives in Beijing, is a doctor.
定语从句练习题（共20题）
1. 用合适的关系代词填空
The girl ______ is sitting there is my sister.
答案：who 或 that
解析：先行词是指人的the girl，关系代词在从句中作主语，所以可用who或that。句意为"坐在那里的女孩是我妹妹。"
2. 用合适的关系代词填空
The book ______ I bought yesterday is very interesting.
答案：that 或 which 或 省略
解析：先行词是指物的the book，关系代词在从句中作宾语，所以可用that、which或省略。句意为"我昨天买的那本书很有趣。"
3. 用合适的关系代词填空
This is the man ______ house was burned down.
答案：whose
解析：关系代词在从句中表示所属关系，修饰house，所以用whose。句意为"这就是那个房子被烧毁的男人。"
4. 用合适的关系副词填空
I remember the day ______ we first met.
答案：when
解析：先行词是表示时间的the day，关系词在从句中作时间状语，所以用when。句意为"我记得我们第一次见面的那一天。"
5. 用合适的关系副词填空
This is the school ______ I studied when I was young.
答案：where
解析：先行词是表示地点的the school，关系词在从句中作地点状语，所以用where。句意为"这是我小时候读书的学校。"
6. 选择正确的句子
A. The man who he is standing there is my uncle.
B. The man who is standing there is my uncle.
答案：B
解析：关系代词who已经在从句中作主语，不需要再用he重复作主语，选项A多了多余的he，是错误的。
7. 选择正确的句子
A. This is the best film that I have ever seen.
B. This is the best film which I have ever seen.
答案：A
解析：先行词被形容词最高级best修饰时，关系代词应该用that而不是which，所以选项A正确。
8. 将两个句子合并为含定语从句的复合句
I know the girl. She is talking to Tom.
答案：I know the girl who/that is talking to Tom.
解析：先行词是the girl（指人），关系代词在从句中作主语，所以用who或that引导定语从句，紧跟在先行词之后。
9. 将两个句子合并为含定语从句的复合句
This is the house. I lived in it last year.
答案：This is the house which/that I lived in last year. 或 This is the house in which I lived last year.
解析：先行词是the house（指物），关系代词在从句中作介词in的宾语，可用which/that（可省略），也可将介词in放在which前。
10. 将两个句子合并为含定语从句的复合句
He told me his reason. He was late for that reason.
答案：He told me his reason why he was late. 或 He told me his reason for which he was late.
解析：先行词是the reason，关系词在从句中作原因状语，所以用why或for which引导定语从句。
11. 找出句子中的错误并改正
The book that I borrowed it from the library is very useful.
答案：The book that I borrowed from the library is very useful.
解析：关系代词that已经在从句中作宾语，代替了the book，原句中的it是多余的，应删除。
12. 找出句子中的错误并改正
My father, that is a doctor, works in a hospital.
答案：My father, who is a doctor, works in a hospital.
解析：这是非限制性定语从句（有逗号隔开），不能用that引导，应改为who。
13. 用合适的关系代词填空
We all like the teacher ______ classes are very interesting.
答案：whose
解析：关系代词在从句中表示所属关系，修饰classes，说明是"这位老师的课"，所以用whose。句意为"我们都喜欢那位上课很有趣的老师。"
14. 用合适的关系代词填空
The little girl ______ I spoke to is my neighbor's daughter.
答案：whom 或 who 或 that 或 省略
解析：先行词是指人的the little girl，关系代词在从句中作介词to的宾语，所以可用whom、who、that或省略。句意为"我和她说话的那个小女孩是我邻居的女儿。"
15. 选择正确的句子
A. I have read all the books which you lent me.
B. I have read all the books that you lent me.
答案：B
解析：先行词是不定代词all，关系代词应该用that而不是which，所以选项B正确。
16. 翻译句子（使用定语从句）
这是我去年参观过的城市。
答案：This is the city that/which I visited last year.
解析：先行词是the city（指物），关系代词在从句中作宾语，所以用that/which或省略，定语从句紧跟在先行词后。
17. 翻译句子（使用定语从句）
告诉我你为什么迟到的原因。
答案：Tell me the reason why you were late.
解析：先行词是the reason，关系词在从句中作原因状语，所以用why引导定语从句，说明"迟到的原因"。
18. 翻译句子（使用定语从句）
我们班有一个父亲是医生的学生。
答案：There is a student in our class whose father is a doctor.
解析：先行词是a student，关系代词在从句中表示所属关系，修饰father，所以用whose引导定语从句。
19. 翻译句子（使用非限制性定语从句）
汤姆是我的好朋友，他来自英国。
答案：Tom, who is my good friend, comes from England.
解析：这是非限制性定语从句，补充说明Tom的情况，要用逗号隔开，且不能用that，所以用who引导。
20. 翻译句子（使用定语从句）
这是我曾经住过的最美丽的地方。
答案：This is the most beautiful place that I have ever lived in.
解析：先行词被形容词最高级most beautiful修饰，关系代词必须用that；关系代词在从句中作介词in的宾语，in可放在句末。