刘莉萍

同位语从句是名词性从句（主语从句、表语从句、宾语从句、同位语从句）的一种。掌握同位语从句可以从以下几个方面入手：

[同位语及充当同位语的形式]

一个名词（或其它形式）对另一个名词或代词进行修饰、限定或说明，这个名词（或其它形式）就是同位语。单词、短语、直接引语以及从句都可以充当同位语。

1. 单词作同位语。

①This is my friend Harry.

②We both come from Hunan.

③We Chinese are brave and hardworking.

④You three take these seats.

这几个句子中Harry，both，Chinese和three都是同位语。

2. 短语作同位语。

①He says that Computertown UK was formed for just the opposite reason， to bring computers to people and make them “people-literate”.

②Wang Li， just back from the training class， was made director of the Maternity Home.

③People， old and young， took to the streets to watch the parade.

这几个句子分别采用了不定式、介词短语和形容词作同位语。

3. 直接引语作同位语。

But now the question comes to their minds，“Did she die young because she was a clone？”

这个句子里则采用了直接引语来充当同位语。

[同位语从句及其位置]

按照同位语的概念，同位语从句就是在复合句中充当同位语的名词性从句，用来表示与之同位的名词或名词短语的实际内容，或对前面的名词或名词短语加以补充说明。一般情况下同位语从句跟在某些名词如news，idea，fact，promise，question，doubt，thought，hope，message，suggestion，words（消息），possibility等（一般的“抽象”名词都可以）的后面，用以说明该名词所表达的具体内容。比如在Ive come from Mr Wang with a message that he wont be able to see you this afternoon.这句中，that从句表示的就是message的内容。有时同位语从句可以不紧跟在它所说明的名词后，而被别的词语隔开，这在语法上叫做分隔式同位语从句，如The thought came to her that maybe she had left the door open when she left home.就是个很典型的例子。还有一些短语及固定句式后的同位语从句，如on condition，on supposition，on the ground（s），on the understanding，with the exception，in spite of the fact，on the assumption及句式There be+no doubt/hope/chance/possibility后的that从句都为同位语从句，如I will come on condition that John is invited.

[同位语从句的引导词]

同位语从句最常见的引导词是that和whether。这里值得提到注意的有两点：一是同位语从句中的that不能省略，二是虽然if和whether都有“是否”的意思，但是if不能引导同位语从句。

以下两个句子分别含有that和whether引导的同位语从句：

①The idea that you can do this work well without thinking is quite wrong.

②The question whether we should call in a specialist was answered by the family doctor.

除了这两个引导词，连接代词what，who，whom，whose和连接副词when，where，how，why也可以引导同位语从句。

①I have no idea what size shoes she wears.

②The question who will take his place is still not clear.

③We havent yet settled the question where we are going to spend our summer vacation.

这三个句子分别含有以what，who和where引导的同位语从句。

[同位语从句和定语从句的区别]

同位语从句和定语从句很容易被混淆，因为它们在句子形式上相近。它们的差别在于：

1. 先行词的区别。

定语从句的先行词是名词或代词，而同位语从句的先行词只能是名词，而且仅限于idea，plan，fact，theory，promise，hope，news，doubt，truth，information，suggestion，question，thought，belief，conclusion等少数名词。

2. 引导词的区别。

首先，that既可引导同位语从句又可引导定语从句，其区别在于：同位语从句由连接词that引导，连接词that本身无意义，在同位语从句中不充当任何成分，不可省略，不可以用其他词替代；而定语从句由关系代词that引导，关系代词that在从句中充当一定的成分，作宾语时可省略。

①The news that you told me yesterday was really exciting.

②We heard the news that our team had won.

在①句中，划线部分是定语从句，that在从句中作宾语，在意义上指代先行词news；在②句中，划线部分是同位语从句，that没有任何意义，只起连接作用。

其次，由when，where，why引导的同位语从句和定语从句的区别在于：同位语从句由连接副词引导，只起连接作用，没有指代作用；定语从句由关系副词引导，关系副词具有指代先行词的作用，常用一个介词加关系代词替换。

①I will never forget the day when I joined the army.

②We have no idea when she was born.

在①句中，划线部分是定语从句，when在从句中作状语，它可以转换成on which的形式；在②句中，划线部分是同位语从句，when在从句中充当状语，但不能转换成“介词+关系代词”的形式。

3. 意义的差别。

同位语从句是用于说明所修饰名词的具体内容的，它与被修饰词语通常可以划等号；而定语从句是限制所修饰名词的，它的作用是将所修饰的名词与其他类似的东西区别开来。

①We are glad at the news that he will come.

②We are glad at the news that he told us.

在①句中，news的内容就是he will come，故that引导的是同位语从句，而②句中，that从句是限制the news的内容的，即我们高兴只是因为他告诉的这个news而不是其他的news，故that从句为定语从句。

[同位语从句的语气]

在suggestion，advice，request，order等意为“建议；命令；要求”的名词后，同位语从句中的谓语动词通常用“should+动词原形”的虚拟语气结构，句中的should可以省略。

①Our teacher gave us some advice how we（should） use the computer.

②She made a request that the doctor （should） be sent for at once.

如果在高考英语试题中，同位语从句出现在语法填空的题型中，特别提示同学们一定要按照三个步骤来完成：第一步确定引导词，第二步注意从句中的语序要用陈述句的句式，最后则要关注从句中的谓语部分的时态语态或者虚拟语气的用法。

[练习]

一、填空题。

1. The news made everybody happy. （take）

飞机将按时起飞的消息让大家高兴。

2. He made a promise when he is free.（hand）

他承诺有空时帮我。

3. You may have no idea when they experienced the first snowfall just before the New yeat. （fun）

你可能不知道，就在新年之前经历第一场雪时他们玩得有多开心。

4. Her mother is worried about the possibility . （dislike）

她的妈妈担心她女儿可能不喜欢上学校。

5. The suggestion was accepted by him， which helps him a lot. （attitude）

他接受了让它保持积极的态度这一建议，而这对他也起了很大的作用。

6. Lucy will win the first place in the final examination. （doubt）

毫无疑问，Lucy将在期末考试中获得第一名。

7. I made a proposal a meeting next Monday. （hold）

我建议下周我们开个会。

二、完成句子。

1. 他还没有做出决定是否去那里。

He hasnt made the decision .

2. 我们做出决定：我们必须立即行动。

We came to the decision .

3. 他提议会议延期。

He made a proposal .

4. 他幸存的希望很小。

There was little hope .

5. 我们女排赢得冠军的消息大大地鼓舞了我们所有人。

The news encouraged us all greatly.

6. 我从王先生那边得知一个消息，他说他今天下午不能来看你了。

Ive come from Mr Wang with a message

.

7. 我们怀疑他们是否能准时完成任务。

We have some doubt .

8. 我们是否需要解决这个问题还没有考虑。

That question has not been considered.

9. 毫无疑问，小麦的价格将会上涨。

There is no doubt .

10. 他们是否能够完成那个项目，这个问题非常重要。

The problem is very important.

三、选择题。

1. Where did you get the idea I could not come？

A. whether B. that

C. if D. what

2. They were all very much worried over the fact you were sick.

A. that B. if

C. whether D. why

3. Along with the letter was his promise he would visit me this coming Christmas.

A. which B. that

C. what D. whether

4. He always works hard even if he knows the fact he is not in good health.

A. what B. whether

C. if D. that

5. Some researchers believe that there is no doubt a cure for AIDS will be found.

A. which B. what

C. that D. whether

[参考答案]

一、1. that the plane would take off on time

2. that he would give me a hand

3. what great fun they had

4. that her daughter dislikes going to school.

5. that he （should） keep a positive attitude

6. There is no doubt that

7. that we （should） hold

二、1. whether he will go there

2. that we must act at once

3. that the meeting be postpone

4. that he would survive

5. that our women volleyball team had won the championship

6. that he wont be able to see you this afternoon

7. whether they can complete the task on time

8. whether we need to solve it

9. that the price of wheat will go up

10. whether they could finish the project

三、1～5 BABDC