with might, may, must ,could, can't.

1.-It could have been worked by a professional, the design is really good.
2.-I must have paid attention to the class, I have understood the topic.
3.-You can't have designed that attire, you're not so imaginative
4.-He might have been going out with his girlfriend, but he decided to study for his exams.
5.-He he could have practiced the entire week, that song was pretty good.
6.-You may have studied medicine, you know too much about of that.
7.-They may have asked for the motor instead of stealing.
8.-She must have been studying all the night, because she passes all her exams.
9.-I can't have been eating the cakes, I was cleaning my bedroom.
10.-We might have been cleaning the sisaster in the living room if it weren't because we've got a lot of homework.