定语从句和同位语从句的区别

定语从句和同位语从句的区别

一、定语从句是形容词从句，其作用相当于一个形容词，是用来修饰前面的名词或代词的；同位语从句是名词从句，其作用相当于一个名词，是对前面的名词作进一步解释的。例如：1． We heard the news that he had told her. 我们听到他对她说的消息。

2． We heard the news that he had won the game. 我们听到消息他赢得了比赛。

例1中的that从句的作用相当于一个形容词，其作用是修饰the news；例2中的that 从句的作用相当于一个名词，是对the news的进一步说明。

二、定语从句的引导词在从句中充当一定的成分，可作主语、宾语、状语等；而同位语从句中的引导词在从句只起连接作用，不作任何句子成分。例如：

1. A plane is a machine that can fly. 飞机是一种能飞的机器。

2. The fact that they didn’t finish the work has to be faced. 必须面对事实，他们没有完成工作。

例1中的引导词that在从句中充当句子成分，作从句的主语，故为定语从句；例2中的that只起连接作用，引导从句解释fact的内容，不作任何句子成分，故为同位语从句。

三、引导定语从句的关联词在从句中作宾语或状语时，可以省略或被其他词代替；而同位语从句的引导词一般不能省略，更不能被代替。例如：

1. The news that she heard is true. 她听到的消息是真的。

2. The news that she will go abroad is true. 她将出国这消息是真的。

例1是定语从句，that可省略；例2是同位语从句，that不能省略。

3. The reason why he was chosen remains unknown. 他为什么被选上的原因还是不清楚。

4. The idea why he was chosen attracted our attention. 他为什么会被选上，这一想法引起我们的注意。

例3中why引导的是定语从句，why可以被 for which或 that 代替；例4中 why引导的是同位语从句，why 不能省去，也不能被其它词代替。

四、同位语从句与其所修饰的名词之间是一种同位关系，二者之间存在逻辑上的系表关系，可用“主+系+表”结构来表示。例如：

The news that he won the first place is true. 他赢得冠军的那个消息是真的。

上句若用“主+系+表”结构来表示，则是： The news is that he won the first place. 消息是他赢得了冠军。

意思合理，系表结构成立，故为同位语从句。

五、定语从句所修饰、限定的先行词可以是各类名词，可以有复数形式；而同位语从句一般都与抽象名词同位，一般没有复数形式。例如：

1. The possibilities that she was offered seemed very great.她得到的可能性似乎大些。

2. Her mother was worried about the possibility that her daughter dislike to go to school. 她的母亲很担心，她女儿有可能不喜欢上学。

例1中的possibilities是定语从句的先行词，可用复数形式；例2中的possibility 是抽象名词，后接的是同位语从句，一般不用复数形式。

六、由when, why, where引导的定语从句分别修饰或说明表示时间、原因或地点的词，但它们引导的同位语从句一般不和表示时间或地点的词同位。例如：

1. I still remember the day when I first came to Beijing. 我仍然记得初次来北

京的那天。

2. I have no idea when she will be back. 我不知道她何时回来。

3. This is the house where I lived two years ago. 这是我两年前住的房子。

4. The question where we shall have a meeting hasn’t decided. 我们到什么地方

去开会，这个问题没有决定。

例1、3中的when和 where引导的是定语从句，day 和house分别表示时间和地点；例2、4中的when和 where引导的是同位语从句。

同位语从句练习题

1.The fact ____ she works hard is well known to us all.

A.that

B.what

C.why

D.which

2.The fact ____ he was successful proves his ability.

A.that

B.what

C.which

D.why

3.The news ____ he was kidnapped surprised us greatly.

A. what

B.that

C.why

D.when

4.His suggestion ____ the meeting be delayed was turned down.

A.which

B.that

C./

D.it

5.I have no idea ____ he will start.

A.when

B.that

C.what

D./

6.I've come from the government with a message ____ the meeting won't be held tomorrow.

A.if

B.that

C.whether

D.which

7.The thought ____ he might fail in the exam worried him.

A.when

B.which

C.what

D.that

8.The order ____ the prisoner be set free arrived too late.

A.which

B.whether

C.that

D.what

9.The nurses are trying their best to reduce the patient's fear ____ he would die of the disease.

A.that

B.as

C.of which

D.which