1.概念：用作主语的从句叫做主语从句。
2.构成：关联词+简单句
3.引导主语从句的关联词有三类：从属连词that。如：That they were in truth sisters was clear from
the facial re百度竞价推广blance between
them.非常明显，她们确是亲姐妹，她们的脸型很像。从属连词whether。如：Whether he’ll come here isn’t
clear.他会不会来这里还不了解。连接代词who,whom,whose,what,which,whoever,whatever,whichever
连接副词 wher,when,how,why。如：What she did is not yet known.她干了什么尚不了解。How this
happened is not clear to anyone.这事如何发生的，哪个也不了解。Whoever comes is
welcome.不论哪个来都欢迎。Wherver you are is my home ---- my only
home.你所在的任何地方就是我的家----我唯一的家。
