Why she didin't come to the party last night.

问题描述:

Why she didin't come to the party last night.
I don't know shy she didn't.
I don't know shy she did.
哪一个对
为什么

前者的意思是 我不知道他为什么没做
后者的意思是 我不知道他为什么做了
原则上讲都对啊,看上下文表达什么意思了,不过know有否定前置,第二句还是比较常见,第一句双重否定了哦.