Nobody knows for sure whether the theory is true or not, but it's a fact that bees are disappearing in very large numbers.

没有人确切地知道这个理论是否正确，但事实是蜜蜂正在大量消失。

youdao

"Nobody knows for sure and certain," said Martha.

“没有人确切知道。”玛莎说。

youdao

Nobody knows for sure.

没人确切地知道。

youdao

So that would be my guess, but nobody knows for sure.

这是我的猜测,没人能确定

耶鲁公开课 - 古希腊历史简介课程节选

Nobody knows for sure how Mr Bush's two appointees, Mr Roberts and Samuel Alito, would vote.

ECONOMIST: The Supreme Court

Nobody knows for sure how the federal fiscal crisis might influence future defense spending.

FORBES: How Northrop Grumman Aims To Outperform

But nobody knows for sure how the currency markets would react were the pact to be diluted or even scrapped.

ECONOMIST: Europe's stability pact