当动词 think, believe, suppose, expect, imagine 后接一个表示否定意义的宾语从句时，其否定通常转移到主句。如：

'I don't think you have much of a case.' — 'I expect not.'

“我想你没有什么好理由。”——“我想没有。”

《柯林斯高阶英汉双解学习词典》


I don’t think that it is worth doing. 我认为这不值得做。

I don’t believe that he will help us. 我相信他不会来。

I don't suppose for a minute that he'll agree (= I'm sure that he won't) .

我认为他决不会同意。

I don't suppose it occurred to you to notify the police.

我看你没想过要去通知警察。

《柯林斯高阶英汉双解学习词典》

You don't suppose they'd start the trip without us, do you?

你认为他们是不会抛下我们就上路的，对吧？

《柯林斯高阶英汉双解学习词典》

I didn't expect you would come.

想不到你来了。

《汉英大词典》

I don't imagine (that) they'll refuse.

我认为他们不会拒绝。

imagine但作“想，想象，猜想”等意思解，其引导的宾语从句不必否定转移。

You can hardly imagine what a hard time your mother had when she was a child.

你妈妈小时候别提有多苦了。

《汉英大词典》

He couldn't imagine why he had let so much time pass without contacting her

他想不通自己为什么过了那么长时间还没有和她联系。

《柯林斯高阶英汉双解学习词典》

I couldn't imagine why he would want to be alone with me

我想象不出为什么他会想和我独处。

《柯林斯高阶英汉双解学习词典》