哪些從句作主語時可用it作形式主語

原則上說，it用作形式主語可以代替下列從句：

1. that從句

It is quite clear that he has read the book. 很顯然，他讀過這本書。(HM)

2. what從句

It doesn’t matter what he says. 他說什么沒關系。(HM)

It was clear enough what he meant. 他的意思是很明顯的。

3. who從句

It hasn’t been decided who will be sent to work there. 還沒決定將派誰到那里工作。

4. how從句

It struck her how gentle he was being. 她深深感到他多么溫存。

5. when從句

It hasn’t been made clear when the conference is to take place. 會議什么時候召開還沒有宣布。

6. where從句

It’s not known where she went. 她到哪里去了沒人知道。

It did not matter much where he lived. 他在哪里住都沒有關系。

7. why從句

It was clear why he had asked for a conference. 他為什么要求召開會議原因很清楚。

8. whether從句

It makes little difference whether we go or stay. 我們去還是留沒有多大差別。

It’s not yet settled whether I am going to America. 我去不去美國還沒定。