宾语从句（The Object Clause）
据留学360介绍，在句子中起宾语作用的从句叫做宾语从句。宾语从句的引导词和主语从句的引导词相同。宾语从句可以作及物动词的宾语，作短语动词的宾语，介词的宾语。
宾语从句：及物动词的宾语
Everybody knows that money doesn‘t grow on trees.
宾语从句：短语动词的宾语
Please go and find out when the train will arrive.
宾语从句：介词的宾语
I am interested in what she is doing.
宾语从句：否定的转移
I don’t suppose you‘re used to this diet.
我想你不习惯这种饮食。
I don’t believe she‘ll arrive before 8.
我相信她8点之前不会到。
表语从句（The Predicative Clause）
在句子中起表语作用的从句叫做表语从句。表语从句的引导词和主语从句的引导词相同。 What the police want to know is when you entered the room.
This is what we should do.
That’s why I want you to work there.
as if, as though, because也可用来引导表语从句。
She seems as if she had done a great thing.
It is because you eat too much.
虚拟语气：表语从句
主语是idea, notion, proposal, suggestion, request等名词时,作表语从句的动词为原形动词或should+原形动词。
My suggestion is that we (should) go and help him.
Our only request is that this should be settled as soon as possible.
同位语从句（The Appositive Clause）
一般跟在某些名词如answer(答案)，hope(希望)，fact(事实)，belief (信仰)，news(消息)，idea(主意；观念)，promise(承诺)，information(信息)，conclusion(结论)，order(命令)， suggestion(建议)，problem(问题)，thought (想法)等后面。例如：
I had no idea that you were here. She told us her hope that she would become a pianist.
He made a promise that he would never come late.
同位语从句：whether
whether可以引导同位语从句，而定语从句不能用whether作为引导词。
He hasn’t made the decision whether he will go there.
I have small doubt whether he is suitable for the job.
同位语从句：what
what可以引导同位语从句，而定语从句不能用what作为引导词
I have no idea what he is doing now.
同位语从句：how
how可以引导同位语从句，而定语从句不能用how作为引导词
It’s a question how he did it