名词性从句和定语从句的主要区别

1、名词性从句和定语从句的主要区别作者：王燕来源：高中生高考指导2013年第01期词性从句和定语从句是高中阶段语法的重点和难点，很多同学不能正确区分这两种从句，导致解题困难。其实，同学们只要对以下几个方面加以注意，问题就可以迎刃而解。同学们首先要熟悉这两种从句的概念，因为概念是判断与区分的标准。名词性从句：在句子中起名词作用的句子叫名词性从句。名词性从句的功能相当于名词词组，在复合句中能担任主语、宾语、表语、同位语等成分。因此，根据它在句中不同的语法功能，名词性从句又可分为主语从句、宾语从句、表语从句和同位语从句。定语从句：用来说明主句中某一名词或代词（有时也可说明整个主句或主句中的一部分）而起定

2、语作用的句子叫做定语从句。定语从句是由关系代词和关系副词引导的从句，其作用是作定语，修饰主句的某个成分，定语从句分为限制性定语从句和非限制性定语从句。一、成分的区别名词性从句充当句子的主要成分，如主语、宾语、表语或同位语。例：Why he didnt come here is not clear to anyone. （画线部分充当句子的主语）I wonder whether/ if he is fit for the job. （画线部分充当句子的宾语）His brothers health is not what it used to be. （画线部分充当句子的表语）He got the

3、 news from Mary that the sports meeting had been put off.（画线部分充当news的同位语）定语从句充当句子的修饰成分，起修饰作用。例：He has two sons who work in the same company. （画线部分修饰two sons）I had never seen such a good film as I watched last night. （画线部分修饰such a good film）二、引导词的不同引导定语从句的关系词按其在从句中所起的作用分为：关系代词：who，whom，which，that，who

4、se，as关系副词：when，where，why关系代词在从句中充当主语、表语、宾语、定语，而关系副词在从句中只起状语作用。引导名词性从句的连接词按其在从句中所起的作用分为：连接代词：whose，who（-ever），what（-ever），which（-ever），whom（-ever）连接副词：when，where，why，how连词：that，whether，if连接代词和连接副词在从句中充当一定的句子成分，而连词在从句中不充当句子成分，只起连接作用。比较后可以得出以下结论：（1）不会出现在名词性从句中的引导词是as。不会出现在定语从句中的引导词有whether，if，what，how以

5、及复合代词。注意：when和where在名词性从句中不能与 “介词+ which” 互换。例：I dont know where he comes from.该句为名词性从句中的宾语从句，此句中的where 不能替换成from which。When the project is to be completed hasnt been known yet.该句为名词性从句中的主语从句，此句中的when 不能替换成at which。（2）关于引导词that。例：That she lost her necklace on the way home made her so worried.He pret

6、ended that he didnt see me.The reason why he came late was that it was raining.I wont believe the fact that he lied to his mother.The train is the last that will go to Suzhou.The school that（which）my sister studied at is far from here.在上面6个句子中，到分别为名词性从句中的主语从句、宾语从句、表语从句以及同位语从句，和为定语从句。通过6个例句可以看出，名词性从句

7、中的that只起引导词的作用，也就是连接作用，无任何意义。定语从句中的that在从句中可充当主语或宾语，有时候可以与which互换。三、引导词含义上的区分定语从句的引导词在语义上具有指代先行词的作用，名词性从句的引导词不具有此功能。如：The only thing that I can do is to give you some money.此句为限制性定语从句，that引导的定语从句修饰先行词the only thing。that既起连接作用，同时在语义上又指代先行词，在从句中作do的宾语。He made another wonderful discovery，which I think

8、is of great importance to science.此句为非限制性定语从句，which引导的定语从句修饰先行词another wonderful discovery。which既起连接作用，同时在语义上又指代先行词，在从句中作主语。That he suddenly fell ill last week made us surprised.此句为名词性从句中的主语从句，引导词that 只起连接作用。The problem is what we should do to protect the earth.此句为名词性从句中的表语从句，引导词what有两个作用：一是起连接作用，二是

9、在从句中作do的宾语。四、名词性从句和定语从句的转换名词性从句和定语从句虽是两种不同的句式类型，但两者是可以相互转换的。（1）由whoever/whatever/whichever/whomever 这些词引导的名词性从句可以转换成相应的定语从句。如：Whoever leaves the room last ought to turn off the light.可转换为：Anyone who leaves the room last ought to turn off the light.（2）由what引导的名词性从句可以转换成定语从句。He has done what he can to

10、 help me.可转换为：He has done all that he can to help me.练一练1.we cant get seems better thanwe have.A. What；what B. What；thatC. That；that D. That；what2. I drove to Beijing for the concert last month.Is that you had two days off？A. why B. when C. what D. where3. I work in a company almost everyone is waiting for a great chance.A. how B. which C. where D. that4. Many people had seen the film were afra