why
for what reason
whereto
whence
wherefore
forwhy
Whyever
whereunto
他为什么到那里去，这对我来说是个谜。
Why he went there is a mystery to me.
我总觉得他讨厌我，但我不知道为什么。
I always feel he has a grudge against me, although I don't know why.
怎么回事？你为什么哭？
What's the matter? Why are you crying?
她为什么总是郁郁不乐的？
Why is she always disconsolate?
他为什么缺席呢？
Why was it that he was absent?
你到底为什么不跟我说实话？
Why on earth didn't you tell me the truth?
我们为什么要怕他呢？
Why is it that we should be afraid of him?
他为什么很少提到他的儿童时代呢？
Why is it that he rarely mentions his childhood?