如何区分定语从句和同位语从句

如何区分定语从句和同位语从句

同位语从句与定语从句的区别：

跟同位语从句的名词通常有new，idea，fact，promise，question，doubt，thought，hope，message，suggestion，word（消息），possibility等。如：

I’ve come from Mr wang with a message that he won’t be able to see you this
afternoon． 我从王先生那里来，他让我告诉你他今天下午不能来看你了。
英语中引导同位语从句的词通有连词 that，whether，连接副词
how,when,where等。（注：if,which 不能引导同位语从句。）如：
l have no idea When he will be
back．我不知道他什么时候回来。
He must answer the question whether he agrees to if or
not.
他必须回答他是否同意这样一个问题。
四、有时同位语从句可以不紧跟在说明的名词后面，而被别的词隔开。 如：
Several
years later，word came that Napoleon himself was coming to inspect them．

几年以后，有消息传来说拿破仑要亲自视 察他们。
The thought came to him that maybe the enemy had
fled the city．
他突然想起可能敌人已经逃出城了。
、同位语从匈与定语从句的区别。

1、同位语从句与前面的名词是同位关系，即说明它前面名词的内容；而定语从句与前面的名词是修饰与被修饰关系，即限定它前面的名词范围，或补充一些情况。如：

The news that l hove passed the exam is true．我通过了考试这一消息是真的。

（同位语从句，即从句所表达的意思就是前面名词的内容。）
The news that he told me just now is
true．他刚才告诉我的消息是真的。
（定语从句，从句对前面名词起修饰限制作用，即“他告诉我的”那个消息，而不是别的消息。）

2、引导同位语从句的that是连词，在从句中不充当任何成份，而引导定语从句的that是关系代词，除起连接作用外，还在从句中充当主语、宾语或表语等。如：

The idea that computers can recognize human voices surprises many people.

计算机能够识别人的声音的想法使许多人感到惊奇。（that在从句中不充当任何成份。） 

最简单的方法就是将that去掉。如果that后面的句子还是完整的，就是同位语从句。

同位语从句和定语从句很相似,但还是有区别的,区别主要在以下三方面:   1. 从词类上区别   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.人们经常讨论大多数劳动力将会在家里工作的可能性?(同位语从句) We are not looking into the question whether he is worth trusting. 我们正在调查的问题不是他是否值得信赖的问题?(同位语从句) Word came that he had been abroad. 据说他已经出国了?(同位语从句) Our team has won the game, which made us very happy. 我们的队赢了,这让我们很高兴?(定语从句) The doctor whom you are looking for is in the room. 你找的那位医生在房间里面?(定语从句) His mother did all she could to help him with his study. 他妈妈尽她的最大努力帮助他的学习?(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. 我们队赢了那场比赛的消息是真的?(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. 昨天他告诉我的那个消息是真的?(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. 我许诺如果谁让我自由,我就让他非常富有?(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. 妈妈做出了一个令她的孩子们高兴的许诺?(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. 我们是否需要它这个问题还没有考虑?(同位语从句) I have no idea what has happened to him. 我不知道他发生了什么事?(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. 我们应派几个人去帮别的几个小组的命令昨天收到了?(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. 我们昨天收到的命令是我们应该派几个人去帮助别的几个小组?(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?) 最后我们在一起来做三道练习题: 1. Along with the letter was his promise ____ he would visit me this coming Christmas.(2004上海春季高考) A. which B. that C. what D. whether 2. The other day, my brother drove his car down the street at ____ I thought was a dangerous speed. (2004上海春季高考) A. as B. which C. what D. that 3. Luckily,we'd brought a road map without ____ we would have lost our way. (2004北京春季高考) A. it B. that C. this D. which

参考资料： http://edu.qq.com/a/20050314/000175.htm

定语从句的先行词可以还原到原来的句子里。

同位语从句不能还原。

1.定语从句的作用相当于形容词，对先行词起修饰、描述或限制的作用；

  同位语从句的作用相当于名词，对先行词进行补充说明，和先行词是同位关系。

2.如果引导从句的词是that

   如果that在句中做成分，是定语从句；

   如果不做成分，是同位语从句。

3.如果引导词为when，where，why

 若其前面的词又分别是表示时间，地点，原因的词，即前后意义相关时，它们为关系副词，引导定语从句

 若前后意义不相干，它们为连接副词，引导同位语从句。