主语从句三要素：
1、关联词不能省略
2、谓语动词用单数
3、从句用陈述语序
常见引导词
what, when, where，which, who, that，whether, how ，whatever, whoever
Whether it will do us harm or good remains to be seen.
I dont think that whatever happens is right.
Is what you told me really true?
NOTICE: What we need most are books.