adv.
为什么

Why are you late?
你为什么迟到?
Why not call on me tomorrow?
你干吗不明天就来看我呢?
That is why I'm working hard at my lesson.
就是这个原因, 我要努力学习。
I can't understand why he failed.
我不明白他为什么失败了。
That is the reason why we must go now.
那就是我们现在必须走的理由。
Why ever didn't you tell us before?
你怎么不早告诉我们呢?
int.
[表示惊奇, 怀疑, 异议, 承认, 发现, 停顿, 思考等的感叹词]
Why, it's nearly nine o'clock.
啊, 快要九点了。
Why, even a child knows that!
哎呀, 这连小孩都知道!
Why, of course, I'll do it.
噢, 当然罗, 我要做的。
Why, yes, I will if you wish.
嗯! 当然, 如果你希望这样, 我就去做。

n.
(pl. whys)
原因, 理由
难解的问题

all the great whys of life
一切难解的人生问题
I cannot explain why.
我说不出理由。
Tell me all the whys and wherefores.
把所有的理由和原因都告诉我