why是什么意思

为嘛

副词 adv. 为什么
for what reason
· Why are you late?
你为什么迟到？
· Why must you be good at a foreign language?
为什么你必须学好一种外语？
· Why not have a rest?
为什么不休息一会儿？

副词 adv. …的原因（理由）
for which;on account of which
· Tell me why you were late this morning.
告诉我你今天早上为什么迟到了。
· Ask him why he did it.
问问他为什么那样做。
· I can't think why she said that.
我不能理解她为什么那样说。

感叹词 int. （表示惊愕或抗议）啊唷；嗨；噢；咳
· Why,it's quite easy.
咳，这相当容易。
· Why,it's far too late.
咳，太晚了。
· You say he's only forty! Why, I know he's at least fifty!
你说他只有四十岁！嗨，我知道他至少有五十岁了！

可数名词 n.[C] 理由；原因
reason
· Tom knows why.
汤姆知道其中原因。
· He looks quite happy. Do you know why?
他看来很高兴，你知道是什么原因吗？

楼主，请注意why有如下用法。

why

adv.
为什么, ...的(理由)
int.
(表吃惊, 满意等)哎呀!什么?<