what 和that、which比较 # What I need now is to lie down and have a good rest. 关系代词what与that或which不同。that与which通常代替前面的名词，并“重复其意思”： I gave her the present which she asked for. 而what 的含义则是the thing(s) that，故上句可写为： I gave her what she asked for. (what = the present which) # what作关系代词时相当于the thing which或the thing that，故应当接一个单数形式的动词。 What we need is more motorways. #What 和that 都可以引导名词性从句。但他们在句子中的语法功能截然不同。 一．在引导名词性从句时，从属连词that一般要注意三个不 1．不省略 当从属连词that引导主语从句、表语从句和同位语从句时，that不省略。 1) That he was able to come made us happy. (That 引导主语从句不可省略) 2)The truth is that I didn’t go there. (that引导表语从句不可省略) 3)The news that our team has won is true. (that引导同位语从句不可省略) 但在非正式文体中that 引导宾语从句时可以省略，除下列两种情况外： that在宾语从句中不能省略的情况. (1). 在主+谓+it(形式宾语)+宾补+that， 从句(真正宾语) 的句型中不省略. He made it quite clear that he preferred to study English.（that不可以省略） (2). 由连词and连接的两个由that引导 的宾语从句中, 则第二个宾语从句前的that不省略。 He told me that he would come and that he would come on time.（第一个That可省略，但第二个that不可） 2．不作成分 that 在名词性从句中不作任何句子成分。 Sydney kept his promise that he would always do anything he could for Lucie to make sure of her happiness.（that引导同位语从句，但在句中不作任何成分, 也不省略） That you don’t like him is none of my business. (that引导主语从句，但在句中不作任何成分，也不省略） 3． 没词义 That she is a rich woman is known to us. (that引导主语从句，但没有汉语意义) The thought that he might fail in the exam worried him. (that引导同位语从句，但没有汉语意义） 二．在引导名词性从句时，What一般要注意一个不,一个有,一个作： 1．不省略 what 引导名词性从句时，what 在句中不省略。这一用法与that 用法不尽相同。 What I had for breakfast today was rice with egg.(what引导主语从句,不省略) I wonder what we can do about it. (what引导宾语从句，不省略） 2．有词义 what 引导名词性从句时，有词义。一般是“----的东西/事情/话等”这一用法与that 用法不一样 This is what she wanted to show us. (what引导表语从句，这是她想让我们看的东西。) What the teacher said had a good effect on the children. (what引导主语从句，老师说的话对孩子们有很好的作用。） 3．作成分 what 在引导名词性从句时，在从句中充当成分。这一用法与that 用法不一样。 It doesn’t matter what he said. (it 是形式主语，what引导主语从句。What 在主语从句中作said 的宾语。) 题——It was true ______Alice did surprised her mother. A. that what B. what that C. that that D. all what 评析： A。it在句中是形式主语，that引导的是主语从句that Alice did surprised her mother.，在这个主语从句当中，what 又引导了主语从句what Alice did，what在从句中作did 的宾语。 三．特别提醒 1. What所引导的从句可以在介词后作宾语，而that从句一般不可以。 1After months of voyage, Columbus arrived in _____later proved to be a new continent. ○A. where B. which C. what D. that 评析：C。在介词in 后面，应用what引导的宾语从句，what在从句中作主语。而that不可以这样用。 2On stepping into his room, he was astonished to find the floor covered with _____looked like tiny insects. ○ A. that B. something C. what D. anything 评析：C。在介词with后面，应用what引导的宾语从句，what在从句中作主语。而that不可以这样用。 2.that可以引导定语从句，而且是定语从句引导词中的顶梁柱，它在定语从句中要充当成分，通常作定语从句中的主语、宾语。同时that也可以引导名词性从句，在名词性从句中that 不充当成分。 但What不可以引导定语从句。它只可以引导名词性从句,在句中相当于 what =all that ,what 在名词性从句中充当成分，常常作主语、宾语和表语。 1All _____I want to know is what he meant. ○A. that B. which C. what D. whatever 2_____impressed me most was ______such a little boy could play the violin so well. ○ A. That ; what B. What ; that C. That ; that D. What ; what 评析：B。第一空是what 引导的主语从句，并在主语从句中作主语。第二空是that 引导的表语从句，that在表语从句中不省略，不作成分，也没词义。 注意！！定语从句的连接词不可以用what． 本文来源：https://www.wddqw.com/doc/992f3cbaf111f18582d05a26.html