=>
2. We shouldn't have asked the other couple to come with us.
3. He needn't have taken a coat.
4. Ann can't have done it on purpose.
5. The bridge might have collapsed because of the storm.
6. He can't have cheated in the exam.
7. The cartoonist might have overestimated the public's sense of humour. 
8. You should have done your homework.
9. They must have run away through a tunnel.
10. She needn't have left the mobile on the table while she wasn't looking.
11. They shouldn't have gone on smoking.
12. She must have repaired the car herself.
13. Mary should have told Steve about us.
14. She might have been told you the truth.
15. She can't have married Ted.