系動詞和系表結構後面的從句都是表語從句.
如:This is my suggestion that you should read more.
主句 This is my suggestion 是主系表結構，從句位於抽象名詞suggestion之後作解釋説明，且引導詞that在從句內不擔當成份。
實義動詞和介詞後面的從句叫賓語從句.如:
表語從句
It sounds like that a train was passing under the house.
The fact remains that we are behind the other classes.
