概述
与另外两种从句不同的是，名词子句在主要子句中扮演主词、受词、补语、同位格等角色，经常是不可或缺的元素，简化之后必须保证子句仍然是名词类(如动名词、不定式片语等)。
注意：简化之后剩余的子句必须维持名词的词类，最常见的结果就是简化为动名词(V+ing)和不定式(to+V)
简化为V+ing
主词位置
主语可省略
That you don't have a cell-phonecan save you a great deal of trouble.
Not having a cell-phonecan save you a great deal of trouble.
主语不可省略
That john was drunk is no excuse for the rude behavior.
John’s drunkeness is no excuse for the rude behavior.
John’s being drunk is no excuse for the rude behavior.
受词位置
主语可省略
I dislike that I am kept waiting.
I dislike being kept waiting.
主语不可省略
I saw that many birds were flying soouthward.
I saw many birds flying soouthward
补语位置
The actor’s greatest achievement is that he has been nominated twice for the Oscar.
The actor’s greatest achievement is having been nominated twice for the Oscar.
同位格
I am happy about the fact that you won the prize.
I am happy about you winning the prize.
I am happy about your winning the prize.
再来一个更明显的
The fact that he is innocent should be obvious to all.
His innocence should be obvious to all.
His being innocence should be obvious to all.
更高级一点的
I’m surprised that there is no index to the book.
I’m surprised at the fact that there is no index to the book.
I’m surprised at there being no index to the book.
简化为To+V
如果名词子句中有语气助动词，可以将语气助动词简化为to+V,然后省略掉无意义的be动词，剩下的就是不定式。
来自直述句的名词子句
- 主词位置
It is important that one should be honest.
It is important to be honest.
To be honest is important.
比较下面两个例子
1.That anyone should go on such a mission takes guts.
2.That John should go on such a mission is suicide.
句1中的主词anyone是空洞的，简化时可以省略
To go on such a mission takes guts.
句2中的John是有意义的，但是需要被限定
For John to go on such a mission is suicide.
如果有[褒贬]语气，则用of
It is kind that you can say so.
It is kind of you to say so.
- 受词位置
I hope that I can get a raise next month.
I hope to get a raise nexy month.
来自疑问句的名词子句
- Information Question
I’ll tell you what you should do.
I’ll tell you
what to do
试比较下面三个句子：
1.I’ll tell you what to do.
2.I’ll tell you when to do the job.
3.I’ll tell you what to do the job with.
句1中省略的原句是what you should do,what作为do的受词
句1中省略的原句是when you should do the job,when作为时间副词
句1中省略的原句是what you should do the job with,what作为介系词with的受词
- Yes/No Question
来自Yes/No Question的名词子句会加上从属连接词whether,如果子句中有助动词，就会变成whether to,例如:
Whether we should go on or not will have to be decided soon.
Whether to go or not will have to be decided soon.
