初中英语语法：定语从句

定语从句（定语可由形容词，名词，代词，数词，分词，副词，不定式以及介词短语来充当，也可以由一个句子来充当，充当定语功能的句子称为定语从句，定语从句在句中的作用当当与形容词，故又被称为“形容词性从句”。定语从句用来修饰名词，代词或整个主句）

先行词：被定语从句修饰的名词，代词等。可以理解为总是出现在定语从句之前的词，而不同于普通形容词修饰名词，被修饰词常位于定语之后。

·The boy who is sleeping is my nephew

·This is the book which my uncle gave me

关系词：引导定语从句的词被称为关系词，根据其作用可分为关系代词（定语从句中作主语，宾语，表语，定语等）和关系副词（定语从句中作状语）

·Don't forget the book that/which I told you to bring（that/which是关系代词，定从中作宾语）

·This is the mountain village where I stayed last year（where是关系副词，定从中作状语）

先行词与关系词的关系：含有定语从句的句子一般分为2层，即主句层（第一层），定语从句层（第二层），先行词通常是主句中的一个名词/代词/整个主句；关系词位于从句句首，起连接主句和从句的作用，同时又代替先行词在从句中充当某种句子成分（一般是主语，宾语，表语，定语，状语）

·This is the man who/that helped me yesterday

第一层：this is the man(the man是先行词，充当定语从句中help的宾语）

第二层：who/that helped me yesterday（who/that是关系代词，在定语从句中作主语）

特别注意：关系词一般紧跟先行词之后引导定语从句，并代替先行词在定语中充当句子成分，因此从句中不能再重复出现相当于先行词的词。

·This is the right book that you are looking for ✔

·This is the right book that you are looking for the book ❌

·This is the right book that you are looking for it ❌

关系代词的用法：

·This is an old computer + It works much slower = This is an old computer that/which works much slower（that/which替代an old computer，连接先行词与从句并在从句中作主语）

·Those shall be punished + Those break the rules = Those who break the rules shall be punished（who代替先行词those，连接先行词与从句并在从句中作主语）

1，who/whom的用法（作宾语who/whom都可以省略，但作介词宾语时只能用whom且不能省略）

·There are many young men who are for him（主语）

·I happened to meet the professor（who/whom）I got to know at a party（宾语可省略）

·I have many friends to whom I am going to send postcards（介宾不可省略）

2，whose的用法

·You're the only one whose advice he might listen to（定语）

·I’d like a room whose window looks out over the sea（定语）

3，which的用法（作宾语可省略，但作介词宾语时不能省略）

·The river which runs through the center of the city brings us lots of pleasure（主语）

·This is the pen（which）you are looking for（宾语，可省略）

4，that的用法

·The river that runs through the center of the city brings us lots of pleasure（主语）

·This is the pen（that）you are looking for（宾语，可省略）

·My hometown is no longer the beautiful place（that）it used to be（表语，可省略）

·It’s not a good order that I can comply to= It's not a good order to which/whom I can comply（作介词宾语介词不可提到that前，若提前需用which或whom）

关系副词的用法（不可省略）

1，where的用法（可用in which/on which/at which/to which等代替）

·Potatoes can be grown in places where it is too cold to grow rice = Potatoes can be grown in places in which it is too cold to grow rice

2，when的用法（可用on which/in which/at which/during which等代替）

·I shall never forget the days when we worked on the farm = I shall never forget the days during which we worked on the farm

3，why的用法（可用for which代替）

·I have come around to explain the reason why I was absent from the meeting = I have come around to explain the reason for which I was absent from the meeting

定语从句中需要注意的事项

主谓一致问题

1，先行词是单数时，从句谓语用单数；先行词是复数时，从句谓语用复数

·Changde is a city which/that has the most delicious Rice noodles

·The students that laugh at the disabled are not good students

2，“one of+可数名词复数”作先行词，从句谓语用复数；“the only/very/right one of+可数名词复数”作主语时，从句谓语用单数

·He is one of the students who were awarded

·He is the only one of the students who was awarded

关系代词that和which，that和who的用法辨析

1，用that不用which的情况

当先行词时all，much，little，few等不定代词或被不定代词修饰时

·You should hand in all that you have

·I did nothing that might hurt you

当先行词是be后面的表语或关系代词本身在从句中作表语时

·He is not the man that he was

·The school is quite different from the one that it used to be

当主句以here，there开头时

·Here is the book that you've been looking for

·There is a seat in the corner that is still not taken

当先行词有the only/the very/the last等修饰时

·Chatting was the only thing that interested her

·These articles are the very ones that should be read

当先行词是序数词/形容词最高级/被该类词修饰时

·This is the best film that has been shown so far in the city

当主句以who/which开头的特殊疑问句时

·Who is the person that is standing at the gate？

·Which of us that knows something about physics？

当先行词既有人又有物的词时

·She took photographs of the things and people that she was interested in

2，用which不用that的情况

当先行词本身就是that时

·What's that which flashed in the sky just now？

在定语从句中作介词的宾语，且介词位于关系代词前时

·I’m looking for a container in which I can put all these coins

3，用who不用that的情况

当先行词是指人的不定代词或指示代词时（one/anyone/no one/all/nobody/anybody/none/those等）

·Those who have good manners will be represented

·Anyone who wants to swim can write his name on a piece of paper

当先行词指人并含有较长的后置定语/在被分割的定语从句中时

·I met a foreigner in the street yesterday who could ask questions in Chinese

·The boy was crying hard who lost his way while looking for his mother

当两个定语从句中一个已经用了that时

·The boy that you met last night is the group leader who studies very hard

当there be句型中有定语从句时

·There were two men who came here