主语从句就是在句中作主语，主语从句的位置与陈述句中主语位置相同的，统观主语从句的考核占有相当比重，下面具体来看一下that引导的主语从句有关考点！
1.that在句中不做成分。当主语从句位于句首时，不能省略：
That he likes books of this kind is very interesting.= It’s very interesting (that)he likes books of this kind.
这是用的最多的一种主语从句,但把这种主语从句放在句首是很少的,只是为了强调或谓语较长时才这样安排.例如：
That prices will go up is certain.
That she is still alive is a consolation.
2.当谓语动词是seem,appear,be a pity.be a wonder,be likely等时，使用形式主语It，而将真正的主语放在句尾，这时从属连词that可省略：It appeared to scientists on earth (that) the stars had moved.
还有一些例如：绝大部分主语从句都借助先行主语放到句子后部去.
a.It be 形容词 that从句：
It is natural that they should have different views.
It was quite obvious that she didn’t want to come.
b.It be 名词 that 从句：
It’s a shame that you’re sick.
It’s a pity that he can’t swim.
c.It 动词（ 宾语或状语） that 从句：
It happened that she wasn’t in that day.
It seems that you’re right.
d.It 动词的被动语态 that 从句：
It’s said that there has been an earthquake in India.
It’s reported that the enemy troops have crossed the border.
