Răspuns:
3. he cannot have been arrived yet
4. must have been working together
5. can t finish her homework this early
6. must have been taking a bath when i rang
7. has not win the prize.
8. must have been looking for new houses
9. can't invite Linda to the party, he hates her
10. must have been planning the project for some time
11. must have been writing a letter
12. must haven't been paying the bill for a while
13. must have been fixed the pipe
