怎么区分从句引导词that和what 的用法？ 举例说说

Question

每次遇到这方面的选择题，总感觉这两个词都合适，所以经常出错

Answer 1

名词性从句中that和what的用法区别

一．that 引导的名词性从句

首先，连接代词that除引导第一个宾语从句时可以省略外，引导其他各类名词性从句皆不能省略。例如：

① It is
required in the regulations that you should not tell other people the password
of your e-mail account.

② ---- Don’t
you think it necessary that he go home at once?

---- but the problem is that
there is no car.

③ There is
much chance that Bill will recover from his injury in time for the race.

④ Our English
teacher told us (that) we all did very well in the examination and that ten of
us got full mark.

以上四个句子中，that 分别引导主语从句，表语从句，同位语从句和宾语从句，除在第四个例句中第一个that
可以省略外，其他的that 均不可省略。

其次，在引导名词性从句时，that不作句子中的任何成分。例如：

① Nobody
believed his reason for being absent from the class that he had to meet his
uncle at the airport.

该句中，that引导同位语从句，但在句中不作任何成分。

② It is our
belief that improvements in health care will lead to a stronger, more
prosperous
economy.

该句中，it 是形式主语，that引导的主语从句才是整个句子的真正主语，that在句中不作任何成分。

最后，在引导名词性从句时，that没有任何词汇意义。

① A warm
thought suddenly came to me that I might use the pocket money to buy some
flowers for my mother’s
birthday.

② Danby left
word with my secretary that he would call again in the afternoon.

在以上两个考例中，that仅起引导同位语从句的作用，没有任何词汇意义。

综上所述，that 在引导名词性从句时具有三大特点：不可省略，不作成分，没有词义。

二． what引导的名词性从句

首先，what 引导名词性从句时，what 在句中不省略。

这一用法与that引导名词性从句时的用法不尽相同。

① He spoke
proudly of his part in the game, without mentioning what his teammates had
done.

what 在该句中引导宾语从句，what 不可省略。

② Great
changes have taken place in that school. It is no longer what it was 20 years
ago, when it was so poorly
equipped.

what在该句中引导表语从句，但在句中不可省略。

其次，what 引导名词性从句时，具有词汇意义。

这是what 与that 引导名词性从句的重要区别之一，What 一般指“----的东西/事情/人/时间/地点等”。例如：

① Do you have
any idea what is actually going on in the
classroom?

what在该句中引导同位语从句并作这个同位语从句的主语，词义为“----的东西、事情”，整个句子的汉语意思是“你知道教室里到底发生了什么事”。

② It is what
you do rather than what you say that
matters.

这是一个强调句型，被强调的部分是由what引导的两个主语从句，what在句中的词义为“----的东西、事情”，整个句子的汉语意思是“关键要看你做什么而不是说什么”。

最后，what 引导名词性从句时不仅只起引导作用，同时还要作句中的某个句法成分。

这一点是what 在引导名词性从句时与that 用法区别的关键所在。

① I just
wonder_________ that makes him so excited.

A. why it does B. what he
does C. how it is D. what it is

这一题的正确答案是D,是一个强调句型作宾语的典型考例，被强调的成分what 在句中不仅只起引导宾语从句的作用，同时在宾语从句中作makes 的主语。

② A modern
city has been set up in what was a wasteland ten years ago.

在这个句子中，what 引导的从句作了介词in 的宾语，同时what 又在宾语从句中充当主语，意思是“……的地方”。值得注意的是，在引导名词性从句时，that 引导的句子一般不作介词的宾语，相反，由what 引导的句子作介词宾语的情况显得更为常见。例如：

③ The other
day, my brother drove his car down the street at what I thought was a dangerous
speed.

本题中，介词at后面用了what引导的宾语从句，what在宾语从句中作主语，而that不可以这样使用。

综上所述，what 在引导名词性从句时具有三大特点：不可省略，作成分，有词义。

Answer 2

句子缺成分 用what 不缺任何成分 用that
如：That he failed in the exam makes his father angry.(去掉that ,主语是一个完整句子)
What he did makes his father angry.（主语缺did的宾语）