为什么你昨晚睡不着？

Why couldn't you sleep last night?

Source: Tatoeba

Sentence Composition

1 为什么 wèishénme
  1. why?
  2. for what reason?
=2 你 nǐ you (informal, as opposed to courteous 您 nín)
=2 你 nǐ you (Note: In Taiwan, 妳 is used to address females, but in mainland China, it is not commonly used. Instead, 你 is used to address both males and females.)
3 昨晚 zuówǎn
  1. yesterday evening
  2. last night
4 睡不着 shuìbùzháo to be unable to sleep