宾语从句引导词有四种：1.纯引导词whether,if,that
2.名词性引导词what,which,who,whom
3.形容词性引导词whose,which,what
4.副词性引导词where,when,why,how
其中名词性引导词who,what,which可以做从句主语.
I don't know what made you so angry.
He asked me who would go there the next day.
There are two books here.Tell me which is the better .