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

But no one knows for sure when or why it began to symbolise peace.

但是没人能够确认橄榄枝什么时候为什么成为了和平的象征。

youdao

But no one knows for sure when or why it began to symbolise peace. There is probably a connection with ancient Greece.

但无人确切知道在什么时候、或者是什么原因橄榄枝成了和平的象征，这有可能与古代希腊有关系。

youdao

That's why when we officially entered the recession or the challenging situation caused by the financial crisis, I keep asking myself, "What should we do?"

由于金融危机而导致的经济衰退,使得公司处于困境，我一直自问，我们能做些什么？

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Or you can say "Why don't we~?" when you are suggesting that you, as well as others, take a particular action.

当你想建议自己与其他人一起做出某种行动时，你可以说“Why don't we~?”。

Why don't 课堂 - SpeakingMax英语口语达人

Why? How could neurons be all or nothing when sensation is very graded?

为什么,既然感觉是渐增的,那神经元又怎会是服从全或无法则的呢

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There was no information about when or why he returned, and no details about whether he would actively take up the duties of office.

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It's not quite clear when or why we forgot about them, but in Tuscany, where I now live, favas are snatched up as soon as they appear, to be shelled at the table and eaten raw with young pecorino.

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The most perplexing aspect of being a parent is that you can (almost) never discern when or why a child will follow your directives, as opposed to hear what you direct him to do and then do the exact opposite.

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