在主语从句中的引导词有哪些？主语从句有什么注意事项？

引导主语从句连词有that,whether,who,what,whatever等
宾语从句：多为that,可以省略
表语从句：be动词的改变形势
定语从句：that,who,whom,whose,where,when,which...
状语从句：that,when,where等可以表示状态的疑问词等

主语从句(Subject Clause)

定义:如果一个句子在复合句中充当一个主语,那么这个句子就是主语从句.

第一部分：常规主语从句，即句子在复合句中充当一个主语

（1）That he finished writing the composition in such a short time surprised us all.

（2）Whether we will go for an outing tomorrow remains unknown.

（3）Who will be our monitor has't been decided yet.

（4） Whom we must study for is a question of great importance.

（5）What caused the accident remains unknown.

（6）Whatever you did is right.

（7）Whose watch was lost is unknown.

（8）What we need is time.

（9）What we need are good doctors.

小结:

（1)引导主语从句连词有that,whether,who,what,whatever等

（2)连词位于句首不能省略

（3)主语从句大多数情况下视为单三,但也有例外,如例9

第二部分：为了防止句子头重脚轻，通常把形式主语it放在主语位置