that與what引導名詞性從句的區別

that引導名詞性從句只起連接作用，在從句中不作任何成分，無意義，在賓語從句通常省略，但在主語從句、表語從句和同位語從句中均不能省略；what除引導從句外，還在從句中作成分，意為“所……的(東西)”，在含義上等于“名詞+that”。如：

1. 用that的例子

That she lacks experience is obvious. 她缺少經驗，這是顯然的。

The police learned that he wasn’t there at that time. 警察獲知他那時不在場。

He realized that she too was exhausted. 他意識到她也精疲力盡。

My idea is that you shouldn’t have left the country. 我的意見是你不應該離開那個國家。

Bob has the mistaken idea that tomorrow is a holiday. 鮑勃錯誤地認為明天是一個假日。

It was quite plain that he didn’t want to come. 很明顯他不想來。

It is natural that they should have different views. 他們看法不同是很自然的。

2. 用what的例子

What (=The thing that) he said was true. 他所講的是事實。

What he had hoped at last came true. 他希望的事終于成為現實。

What he said is beneath contempt. 他說的話不值一理。

What he says is true, possibly. 或許他說的是對的。

What she saw gave her a fright. 她看到的情況嚇了她一跳。

What I want to say is this. 我想說的是這一點。

I’m sorry for what I said. 我為我說的話表示歉意。

That’s what I want to know. 這是我想知道的。

You had better hear what I have to say. 你最好聽聽我的意見。

I managed to get what I wanted. 我設法得到了我要的東西。

It was what he meant rather than what he said. 這是他的原意而不是他的原話。

There’s something in what he says. 他的話有些道理。

Her interest was roused by what he said. 他的話引起了她的興趣。

He was always conscious of the fact that she did not approve of what he was doing. 他一向清楚她不太贊成他的做法。

注：that 可引導同位語從句，what不能。如:

Have you any idea what time it starts? 你知道什么時候開始嗎?