连词代词what, who, which, whose等引导的主语从句。
What we need is more time.
Who was responsible for the accident is not yet clear.
Whose book it is not important.
Which school you want to go matters much.
连接副词when, where, why, how引导的主语从句。
Why he did this is not known.
When he will come is still unknown.
It is not known why he did this.
How he succeeded is unknown to us.
Where we should hold the meeting needs to be discussed.
Whoever told you to give up smoking was quite right.
Whatever he gave you should be handed in.
Whoever told you that was lying.
Whoever comes is welcome.