同位语从句

同位语从句

1.什么是同位语从句？

在主从复合句中作同位语的从句称为同位语从句，常放在fact, news, idea, truth, hope, problem, information, wish,promise, answer, evidence, report, explanation, suggestion, conclusion等抽象名词后面，说明该名词的具体内容。换言之，同位语从句和所修饰的名词在内容上为同一关系，对其内容作进一步说明。

例：The news that they had won the game soon spread over the whole school.

他们比赛获胜的消息很快传遍了整个学校。

析：they had won the game说明The news的全部内容，因此该句为同位语从句。

2.引导词有哪些？怎么用？

同位语从句一般用that, whether，what, which, who, when, where, why, how等词引导。

补充：

when，where和why引导的定语从句和同位语从句之区别：

when,where和why作关系副词引导定语从句时，有跟它们含义相应的先行词，且先行词在从句中充当一定成分。当when,where和why作连接副词引导同位语从句时，则没有与它

们含义相应的先行词。所以，只要看先行词就可以判定了，若先行词和引导词关系密切，就是定从；只是修饰关系，就是同位语从句。

试比较：

I'll never forget the day when(=on which)we met for the first time.(定语从句)

I have no idea when we met for the first time(同位语从句)

The office where(=in which)you work is here.(定语从句)

Then arose the question where we were to get so much money.(同位语从句)

The reason why(=for which)he did not come is quite clear.(定语从句)

Xiao Wang has solved the problem why the TV was out of order.(同位语从句)

以上例句中when,where和why作关系副词引导定语从句时，可以改为“介词+关系代词which”来引导；而引导同位语从句的when,where和why就不能这样改。

由此可知，why引导的若是同位语从句，先行词就不会是reason或其同义词；若是reason 或其同义词作先行词，就一定是定语从句。所以，只要看先行词就可以判定了。

同位语从句前面的名词只能是idea, fact, news, hope, belief, suggestion, proposal, word, thought, doubt, truth, possibility, promise, order等有一定内涵的名词；而定语从句的先行词可以是名词、代词，主句的一部分或是整个主句。如:

The possibility that the majority of the labour force will work at home is often discussed. （同位语从句）

We are not looking into the question whether he is worth trusting.（同位语从句）

Word came that he had been abroad.（同位语从句）

Our team has won the game, which made us very happy.（定语从句）

The doctor whom you are looking for is in the room.（定语从句）

His mother did all she could to help him with his study.（定语从句,代词all作先行词）

2. 从性质上区别

定语从句是从句对其先行词的修饰或限制,属于形容词性从句的范畴;而同位语从句是从句对前面抽象名词的进一步的说明和解释,属于名词性从句的范畴。如:

The news that our team has won the game was true.（同位语从句,补充说明news到底是一个什么消息.）

The news that he told me yesterday was true.（定语从句,news在从句中作told的宾语）

I made a promise that if anyone set me free I would make him very rich. （同位语从句,补充说

明promise到底是一个什么诺言.）

The mother made a promise that pleased all her children. （定语从句,promise在从句中作pleased的主语.）

3. 从引导词及其在句子中的成分上区别

有些引导词如how, whether, what可以引导同位语从句,但不能引导定语从句.如:

That question whether we need it has not been considered. （同位语从句）

I have no idea what has happened to him. （同位语从句）

引导词that引导定语从句时,在从句中一般作主语或宾语（指物时还可以用which代替）,并且作宾语时常常省略。that在同位语从句中仅起连接作用,不充当任何成分,并且不能省略,也不能用which来代替。如:

The order that we should send a few people to help the other groups was received yesterday. （同位语从句,是对order的具体解释,that虽不作成分,但不能省略。）

The order that we received yesterday was that we should send a few people to help the other groups. （定语从句,是名词order的修饰语,that在从句中作received的宾语,可以省略。）

补充：

当主句的谓语较短，而同位语从句较长时，同位语从句常后置。

如：The thought came to him that maybe the enemy had fled the city.