Whether the sound came from his head or from the hollow tree, that no one could say with certainty.

没有人能肯定地说，这声音是从他的脑袋里发出来的呢，还是从空树里发出来的呢？

youdao

I can say with certainty that this is true.

我可以很确定地说这是真实的。

youdao

One thing we can say with certainty is that leading in the polls is no guarantee of victory.

有一点我们可以肯定，民意调查的领先者并不能保证能够获胜。

youdao

"There is,I think we can say with certainty, that there is not much interest, this is an overstatement.

VOA: standard.2009.11.05

It's perfectly inscrutable as far as I'm concerned. But I think I can say with absolute certainty that one of its possible significances cannot be that the unprofitable servant should have waited to make his investment.

这对我来说很神秘，但我可以说,我很确信,它可能的含义之一,不会是让那个无益的仆人去等。

耶鲁公开课 - 弥尔顿课程节选

It is impossible to say with certainty why justice was never done in Ms. Zhu's case.

WSJ: Review & Outlook: A Chinese Search for Justice

No doctor interviewed for this story was willing to say with certainty that Natrecor was dangerous.

FORBES: J&J's Vioxx-Like Bind

In fact, the one thing we can say with certainty is that we are wrong.

CNN: Don't be like Washington; listen to other views