must have been 后什么时候加过去分词、什么时候加现在进行时，。/

Question

如题所述

Answer 1

被动语态用 must have been done 对过去的一种推测
You must have been finished your work last week.
进行时用 must have been doing
you must have been learning english for 3 years.本回答被提问者采纳

Answer 2

看标志词。