We cannot say for sure what will happen.

我们说不准将会发生些什么。

《柯林斯英汉双解大词典》

But they cannot say for sure who is fighting whom-or why.

但是他们不能确切说出谁在和谁打仗——或是为了什么。

youdao

I cannot say for sure if it was your visual illusion.

我不能肯定这是不是你的视错觉。

youdao

"While we cannot say for sure, it does seem plausible, " said Miller.

CNN: Two quakes in the same region in a day - coincidence?

If we cannot say for sure that a user is in the UK, we cannot show them our rights-restricted content or live-streaming content.

BBC: Your guide to the BBC Embedded Media Player

We cannot say for sure.

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