It may be that some have them already, but we cannot be sure.

也许有些人已经拿到了，但我们不能确定。

youdao

I cannot be sure.

我不能肯定。

youdao

The researchers, from the respected Harvard University in the US, cannot be sure why this is the case.

美国知名学府哈佛大学的研究人员还不能够对此给出一个明确的解释。

youdao

"And while we will continue to do everything we can, we cannot be sure what the future will hold, but we are doing our absolute level best."

VOA: standard.2009.07.29

But he says he cannot be sure why Mariam Khatib died until the samples are analysed.

BBC: Middle East

But he cannot be sure that the commission's recommendations will conform to the government's modest wishes.

ECONOMIST: Lords reform

Although now plainly well placed to win the presidency, the Colonel cannot be sure of it.

ECONOMIST: The colonel rides on