i think he must have been a mechanic,中的must和have been是什么词啊?

i think he must have been a mechanic,中的must和have been是什么词啊? He must have been ill,___ he? 关于must have been MUST have been done must have been He must have been的用法. he must have been there before----- i must have been blind enough that i couldn't see he was a h must have/ must have been的区别 must have been done must have done can't have been和must have been i must have watched 和 i must have been watch TV意思一样吗 为什么