What we need to ask now, is who and why.

我们想问敌人是谁，为什么攻击。

youdao

We want to get at the truth. Who killed him? And why?

我们想查明真相。谁杀了他？为什么？

《柯林斯英汉双解大词典》

For example, the audience learns through a letter or through someone else's conversation who this mysterious gentleman is and why he left the town many years before.

例如，观众通过一封信或其他人的谈话得知这位神秘的绅士是谁，以及他多年前为什么离开这个城市。

youdao

"If you get a doctor who is away in the village and has come across a case he or she thinks is beyond him or her, why cannot that doctor be able to link up easily with a senior doctor in Korle Bu to get advice on it?

VOA: special.2009.06.17

You didn't know who wrote it, where, when, how, why, and someone says to you, "I want you to draw some conclusions about that piece of writing.

你不知道是谁，在哪里，什么时间，怎么样，为什么要写,然后你被要求对篇文章，做一个总结。

耶鲁公开课 - 旧约导论课程节选

Those of you who think it's not okay, none of these, should ask yourself why and should then scrutinize your reasons.

认为有问题的人，觉得这些例子都有问题的应该问自己为什么,然后仔细推敲自己的理由。

耶鲁公开课 - 心理学导论课程节选

The judge also said that he will look into this matter, who and why kept him for three days.

CNN: 'Butcher of Bosnia' held after decade-long hunt

Call and tell us who and why.

NPR: Political Junkie: Three Weeks to Pennsylvania

His family believe it could hold details of his life as an informant and potential clues about who killed him and why.

BBC: Denis Donaldson: Life and death of secret agent