定语从句易错点

定语从句在句中起到形容词的作用，是高考热点。学生对which和that的使用经常混淆。下面把定语从句中关系词使用的特殊情况进行归纳。

限制性定语从句

1. 当先行词在主句中作表语，而且关系代词也在从句中作表语时，关系代词常常用that。

Lianyungang is no longer the city that it was to be.

2. whose 既可以指人，也可以指物，表示所属关系，不可省略。whose +名词这种结构还可以用the +名词 of which （whose） 来替换，也可以用 of which （whose） 来替换。

This is the new machine whose parts are too small to be seen.

（这里的whose parts = the parts of which = of which the parts）

There comes the scientist whose achievements are well-known.

（其中的whose achievements = the achievements of whom = of whom the achievements）

3. 介词+关系代词which /whom

（1） 当介词放在关系代词前面时，关系代词只能用which（指物）或whom（指人），而且关系代词不能省略。

Have you found the pen with which you wrote the note？

In the dark street， there wasnt a single person to whom she could turn for help.

（2） 介词+ which /whom +不定式结构

The wealthy man has a large house in which to live.

4. 当先行词被such修饰，关系代词只用as。

They have found such materials as are used in their workshop.（先行词materials被such修饰，关系代词只用as，且as在定语从句中作主语。）

The house was sold at such a high price as people expected.（先行词price被such修饰，关系词只用as，且as在定语从句中作宾语。）

比较下面的一组句子：

The teacher gave us such a difficult problem as no one can solve.（定语从句）

The teacher gave us such a difficult problem that no one can solve it.（状语从句）

5. the same as 与the same that 含义不同

This is the same magazine as I bought yesterday. 这本杂质跟我昨天买的一样。

This is the same magazine that I bought yesterday. 这就是我昨天买的那本杂志。（同一本）

6. 当way（表“方式、方法”）作先行词时，如果在定语从句中作主语或作宾语，关系代词用that /which，而当它在从句中作状语时，关系代词可用that /in which 或不填。

I like the way （that /which） he used in his work.（作used宾语）

I dont like the way（that/in which /不填）he treats his parents.

7. 当reason作先行词时，先行词在句中作状语时，关系词是why（for which）；如果先行词reason在句中作为主语或者宾语，仍然用which或that。

Can you believe the reason that /which he gave at the meeting？

Do you know the reason why （= for which） he was absent？

8. 英语中有几个词，像point， case， stage， situation， degree作先行词，大体表示“地步，境地，情况”，并且它在定语从句中既不作主语，也不作宾语的情况下，关系词常用where。

He has reached a point where he has to make a decision himself. 而occasion 则常常与when连用。

The occasion arises when he can go abroad to study.

非限制性定语从句

1. 在非限制性定语从句中，即使先行词在定语从句中作宾语，关系词也不能省略。

He has a close friend， who works as a doctor.

His home is near the museum， which we visited last week.

2. 在非限制性定语从句中，当表示先行词的一部分时，也可用名词/代词+ of + which （whom） 来表示。

I have some friends， several of whom are business men.

或者I have some friends， of whom several are business men.

There are about 140 kinds of snakes in Australia， most of which are not dangerous.

或者There are about 140 kinds of snakes in Australia， of which most are not dangerous.

3. 关系代词as、which引导非限制性定语从句的区别

（1） as和which都可以替代主句的整个内容（which还可以替代一个词），as引导的非限制性定语从句即可放在主句前，又可在主句后，有时还可以插入主句中，而which引导的非限制性定语从句一般置于主句之后。

By serving others， a person focus on someone other than himself or herself， which can be very eye-opening and rewording.

A. who B. which C. what D. that

Many animals sleep a lot when young， but sleep much less when they get older， just as is the case with human being.

A. as B. which C. what D. it

（2） as引导的非限制性定语从句的内容与主句往往是相符的，一致的，常常是肯定的，所以as常与以下关系词连用：as is often the case， as is said， as is reported， as is mentioned above， as is known等，而which引导的非限制性定语从句与主句内容常常是不相符的，不一致的，否定的。

As you know， the earth travels around the sun.

He came late， which is unexpected.

（3） 当非限制性定语从句句型为宾语补足语结构时，常常用which引导。

He was late， which made his teacher surprised.