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

To me, that would have been crucial; after all, I wouldn't tell a child there is no Santa Claus or why I am an atheist without a parent's permission.

对我来说，这却很重要；毕竟，如果没有孩子父母的同意，我绝不会告诉一个孩子，圣诞老人是不存在的，或者向他解释为什么我是一个无神论者。

youdao

When it comes to the letter grade on your test or homework, you might notice that there is no letter. Have you ever thought about why that is so?

当涉及到你的考试或家庭作业的字母分数时，你可能会注意到没有字母。你想过为什么会这样吗？

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

Why should I act in such a way if I have no expectation or reasonable expectation that those around me will reciprocate?

如果我对别人的报答,没有期望或合理的期望,我为什么要这样做？

耶鲁公开课 - 政治哲学导论课程节选

So it's easy to see why we might be tempted to say no mere machine could think or reason or have beliefs or desires.

所以很容易明白,为什么机器无法做到,我们刚才讨论的那些特质

耶鲁公开课 - 死亡课程节选

Quinn also isn't afraid to go into uncomfortable places, such as defending gun owners to a liberal crowd in New York or wondering why no one makes fun of President Barack Obama.

WSJ: Colin Quinn has fun with the US Constitution

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

BBC: Hugo Chavez returns to Venezuela after Cuba cancer care

Just how far or why, no one really knows.

ECONOMIST: Italians don't know, but they blame the euro