名词性从句
名词性从句包括宾语从句、主语从句、表语从句、同位语从句。

名词性从句一共有三种：1）that从句；2）whether从句；3）疑问词所引导的从句。

分项说明如下：
1）that从句
任何一个主语起首的陈述句前面冠以that，即成that从句。

He enjoys dancing. That he enjoys dancing.
2）whether从句
由可用yes/no回答的问句，即一般疑问句变化而成。

a) 问句有be动词时：Is he happy? Whether he is happy.
b) 问句有一般助动词（can, will, may, should, ought to, must, have）时：
Can he do it? Whether he can do it
c) 问句有do, does, did等助动词时：主语与助动词还原，再将do, does, did去掉，后面的动词依人称和时态变化。

Did he come? Whether he came
3）疑问词所引导的从句
由疑问词（when, what, how, where, why）等引导的问句，即特殊疑问词，变化而成。

a) 问句有be动词时：What is he doing? What he is doing.
b) 问句有一般助动词（can, will, may, should, ought to, must, have）时：
主语与助动词还原，前面保留疑问词。

Where can he find it? Where he can find it.
c) 问句有do, does, did等助动词时：
主语与助动词还原，前面保留疑问词，再将do, does, did去掉，动词依人称和时态变化。

What did he write? What he wrote.
注：
Who, what, which为疑问代词，若在问句中作主语，变成名词性从句时，结构不变。

Who came here? Who came here.
名词性从句的功能：
1）作主语
Where he lives is still in doubt.
2）作及物动词的宾语
I know that he will go abroad in the near future.
3）作介词的宾语
a)此时仅能用whether从句或疑问词引导的名词性从句作宾语。

That从句不可作介词的宾语。

I am worried about whether he can do it.
prep. o.
I am curious about how he’ll cope with the problem.
b)遇有介词，且非要使用that从句时，其补救方法如下：
①介词+ the fact + that从句，如此就可用the fact作介词的宾语，而that从句就成了the fact的同位语。

I am sure of the fact that the team has won the game.
prep. o. 同位语
I am worried about the fact that he doesn’t study.
②保留介词，不加the fact，但介词之后的that从句要做下列变化：
除去that；that后的主语变成所有格；动词变成动名词。

I am worried about that he plays around all day.
prep. his playing
I am worried about his playing around all day.。