在復合句中充當表語。

1. that在引導表語從句時無含義，不作成分，通常不省。

1)表示事實、真理等的實際內容。

The fact is that he is lying.

The odds are that he will not do it.

2)表示某人的意見、信念等的實際內容。

Our belief is that things will improve.

The trouble is that we are short of money.

2. whether引導表語從句(不可用if)

His first question was whether holmes had arrived yet.

The question is whether people will buy it.

3.連接代詞引導的表語從句。

This is what i want.

The question is who can be chosen to be manager of the company.

My question is which of them is better.

4.連接副詞引導的表語從句。

The problem seemed how we could make him understand it.

The question is where we should go.

5. as if, as though引導的表語從句(常用虛擬語氣)

He looks as if he were angry.

It looks as if it's going to rain.