adv (1)为什么(for which reason)(作疑问词)： W～are you late again/angry/so happy today? 你为什么今天又迟到了/生气/如此高兴? W～didn't you ask my advice/select a nice subject? 你为什么不征求我的意见/选择一个好的题目?Do you know～he didn't come/such an accident happened? 你知道他为什么不来/会发生这样的事故吗?

(2)为什么要(on which grounds)：W～split hairs over such triflings? 为什么对这样的琐事斤斤计较呢?W～bother to go there yourself/risk breaking the traffic law?为什么要亲自去/冒险违反交通法规呢?W～is that? 为什么要那样?

(3)因由(reason for which)(作关系词，尤用于reason 之后)： That's the reason～I'm so tired/came early. 这就是我疲倦/早来的原因。Give me one good reason～I should help you! 讲出我为什么应该帮助你的一个正当理由! Is that～you did it? 这就是你干那事儿的理由吗? W～he shot her isn't important. 他向她开枪的原因并不重要。

why ever (表示惊讶)究竟，为什么，怎么：W～ever didn't you tell me earlier? 你怎么不早告诉我呢? W～ever did he do such a thing? 他究竟为什么做这样的事?

why not (用来提建议或同意某一建议)为什么不：W～not try it again/get down to business now? 为什么不再试一下/现在就着手办正事呢? “Can I come， too? ”“I don't see～not.”“我也能来吗? ”“为什么不能呢? ”W～not? 为什么不呢?

interj 嗨，呦(used to express surprise or impatience，etc)(用以表示惊讶或不耐烦等)：W～，here's what I was looking for. 啊!这正是我在寻找的。W～!W～! The box is empty! 哎呀!哎呀!盒子是空的!W～，what a bruise you have got! 哎呀!你怎么伤成这样!

n原因，疑难事(reason or something unknown)[C]： Every～has a/its wherefore.(prov) 凡事必有因。Life is full of～s. 生活中充满了许多不解之迷。

the whys and (the) wherefores 缘故，理由： I don't want all the～s and the wherefores，but the results. 我不想知道任何的缘由，只要结果。〖同〗reason