3. There is no doubt that....

一、作不可数名词,作"疑惑;怀疑"

①肯定句中doubt多接whether (一般不用if代替) 同位语从句。如:

There's some doubt whether he'll keep his promise. 他会不会信守诺言还难说。

She had her doubts whether the new book would sell well. 她怀疑新书是否会畅销。

②否定句中doubt多接that同位语从句。如:

There is no doubt that they will ask you for help. 毫无疑问,他们会请你帮忙的。

I have no doubt that you will succeed. 我毫不怀疑你会成功的。

二、作及物动词常用于下列句型中,作"怀疑;不能肯定;不大相信"解,一般不用进行时态。

①用于否定句或疑问句,后接that引导的宾语从句。如:

I don't doubt that he is telling the truth.

我毫不怀疑他在讲真话。

Do you doubt that he will win the match?

你怀疑他会赢这场比赛吗?

②用于肯定句,一般接whether 或if引导的宾语从句.如:

I doubt whether we will make a profit out of it. 我认为我们不可能从此事中获利。

We doubt if she will be persuaded.