你应该是去睡得很晚。

You must have stayed up late.

Source: Tatoeba

Sentence Composition

=1 你 nǐ you (informal, as opposed to courteous 您 nín)
=1 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.)
2 应该 yīnggāi ought to; should; must
=3 是 shì
  1. to be (followed by substantives only)
  2. correct; right; true
  3. (respectful acknowledgement of a command) very well
  4. (adverb for emphatic assertion)
=3 是 shì variant of 是 shì
4 去 qù
  1. to go
  2. to go to (a place)
  3. (of a time etc) last
  4. just passed
  5. to send
  6. to remove
  7. to get rid of
  8. to reduce
  9. to be apart from in space or time
  10. to die (euphemism)
  11. to play (a part)
  12. (when used either before or after a verb) to go in order to do sth
  13. (after a verb of motion indicates movement away from the speaker)
  14. (used after certain verbs to indicate detachment or separation)
5 睡 shuì
  1. to sleep
  2. to lie down
6 得很 dehěn (after an adjective) very
7 晚 wǎn
  1. evening
  2. night
  3. late