Ronald Carter, Rebecca Hughes and Michael McCarthy

在Exploring Grammar in Context (Unit12) 有讲到这个问题

我不太清楚题目说的“疑问分句，不是名词性关系分句”是什么意思？难道名词性从句带点疑问含义，就不是名词性从句？----这点其实不重要，只要学语法不是只为学几个语法术语就行。重要的是，学了一个语言现象，可以解决什么问题。

what 从句是一个名词性从句，可以做主语。

主语从句如果太长，可以用形式主语it来代替它，而将这个主语从句后置。

不过，what主语从句有两种情况:

一种可以后置：

What we should do next is not decided yet.

à It is not decided yet what we should do next.

这里的what-有疑问的意思在里面，与when、where、why 等wh-词引导的主语从句一样，可以后置。谓语(部)常为 is a question, has not been decided yet, is not known yet 等等。

另一种情况则不能后置：

What you said is not right. 不能说：It is not right what you said.

What makes his headmaster unsatisfied with him is (that) he often breaks the school rules.

这个肯定是对的，但是它不能用it来代替，而把what后置。

它也不能用It is...that 再强调。读者可以自己试试，再强调会得出什么结果。

语法是对语言现象的大体归纳，不能教条。

其次，读书各人也有各人的理解层次问题，所以建议自己看书，

有了问题，针对书里具体的疑问点，大家一起讨论。

Was it clear what he was saying?

It wasn't immediately clear what he was talking about.

he immediately made it clear what he wants us to do。

NBA insider has made it clear what he will do in free agency.

---随便用 "clear what he" 拉了几个句子，

真没闲工夫去看what- 部分带不带疑问含义。

===附===

不光是what-, 其它的wh-也存在不能二次强调的问题

How we did it was by giving each person a number instead of a name.

Where we went wrong was that we turned left instead of right.

Why I rang you was because I needed to check something.

How he behaved was terrible.

Where he lived was in New York.