●定语从句

一、定语从句的概念

在复合句中，修饰某一名词或代词的从句叫定语从句。被修饰的名词或代词叫先行词，定语从句一般放在先行词的后面。

二、定语从句的关系词

引导定语从句的关系词有关系代词和关系副词，常见的关系代词包括that, which, who（宾格whom，所有格whose）等，关系副词包括where, when, why等。关系代词和关系副词放在先行词及定语从句之间起连接作用，同时又作定语从句的重要成分。

三、定语从句的分类

根据定语从句与先行词的关系，定语从句可分为限制性定语从句及非限制性定语从句。限制性定语从句紧跟先行词，主句与从句不用逗号分开，从句不可省去，非限制性定语从句主句与从句之间用逗号分开，起补充说明作用，如省去，句子意思仍完整。

四、关系代词的用法

1．that既可以用于指人，也可以用于指物。在从句中作主语或宾语，作主语时不可省略，作宾语可省略。例：

Mary likes music that is quiet and gentle. （that作主语）

The coat (that) I put on the desk is blue. （that作宾语）

2．which用于指物，在句中作主语或宾语，作主语不可省略，作宾语可省略。例：

The building which stands near the train station is a supermarket. （作主语）

The film (which) we saw last night was wonderful. （作宾语）

3．who, whom用于指人，who用作主语，不可省略。whom用作宾语，在口语中，有时可用who代替whom，可省略。例：

The girl who often helps me with my English is from England. （作主语）

Who is the teacher (whom) Li Ming is talking to? （作宾语）

［温馨提示］

（1）当定语从句中含有介词，介词放在句末时，who, that, which可省略，但介词在关系代词前时，只能用“介词＋which/whom”的结构。例：

This is the house in which we lived last year.

Please tell me from whom you borrowed the English novel.

（2）含有介词的固定动词词组中，介词不可前置，只能放在原来的位置上。例：

This is the person whom you are looking for.

（3）that作介词的宾语时，介词不能放它的前面，只能放在从句中动词的后面。例：

The city that she lives in is very far away.

（4）关系词只能用that的情况：

①先行词被序数词或形容词最高级修饰，或本身是序数词、基数词、形容词最高级时，只能用that，而不用which。例：

He was the first person that passed the exam.

②被修饰的先行词是all, any, much, many, everything, anything, none, the one等不定代词时，只能用that，而不用which。例：

Is there anything that you want to buy in the shop?

③先行词被the only, the very, the same, the last, little, few等词修饰时，只能用that，而不用which。例：

This is the same bike that I lost.

④先行词里同时含有人或物时，只能用that，而不用which。例：

I can remember well the persons and some pictures that I saw in the room.

⑤以who或which引导的特殊疑问句，为避免重复，只能用that。例：

Who is the girl that is crying?

⑥主句是there be结构，修饰主语的定语从句用that，而不用which。例：

There is a book on the desk that belongs to Tom.

（5）只能用which，而不用that的情况：

①先行词为that, those时，用which，而不用that。例：

What's that which is under the desk?

②关系代词前有介词时，一般用which，而不用that。例：

This is the room in which he lives.

③引导非限制性定语从句，用which，而不用that。例：

Tom came back, which made us happy.

五、关系副词的用法

1．when指时间，其先行词表示时间，在句中作时间状语。例：

This was the time when he arrived.

2．where指地点，其先行词表示地点，在句中作地点状语。例：

This is place where he works.

3．why指原因，其先行词是原因，作原因状语。例：

Nobody knows the reason why he is often late for school.