No one knows for sure when or why it began to symbolize peace.

没有人确切地知道它是什么时候或者为什么开始成为和平的象征。

youdao

Nobody knows how they do it with such accuracy, or why eels spawn where they do.

没有人知道它们如何做到那么准确，或是鳗鱼为什么要在大海里产卵。

youdao

youdao

Experts say one of the reasons the gunfight is so interesting to many people is that no one knows who shot first or why.

VOA: special.2010.02.15

The first question you need to ask yourself is why do you want, or why are you thinking about taking this course?

各位需要问自己的第一个问题是，为什么要，为什么想研读这门课程？

耶鲁公开课 - 新约课程节选

I don't see the need why people need to go to college first or for that matter even go to law school.

我认为没有必要先上本科，然后再上法学院，甚至没必要上法学院。

想成为律师的话 - SpeakingMax英语口语达人

Why not wait for them, or why not include them more in the talks?

WHITEHOUSE: Press Briefing

Or why the scout troop built a treehouse on the very top of a tree.

WSJ: The World of Filmmaker Wes Anderson

It was unclear exactly whom the cheers and the boos were meant for or why.

CNN: Kerry, Bush daughters booed on MTV