It代替主语从句作形式主语放于句首，而把主语从句置于句末。主语从句后面的谓语动词一般用单数还是复数？

Question

如题所述

Answer 1

很简单，将主语从句看成一个个体it，由于it是单数，故主语从句后面需要用单数。举几个例子给楼主吧：
1.It was clear from the facial resemblance between them (that they were in truth sisters).很明显，她们确是亲姐妹，她们的脸型很相似 这里是was 注：括号内为主语从句，下同
2.It is not known yet （whether they will come today），他们今天是否会来还不知道。这里是is
3.It is said (that he's got married),这里也是is
4.疑问句中：Is it probable (that it will rain today)?
还有很多其他的例子，不便一一举出，但可以确定的主语从句后面的be动词是都用单数形式，希望能帮到楼主！

Answer 2

用单数。 如 It takes sb. st. to do sth. it is + adj. for sb to do 等句型就可以看出来用单数形式