1. You needn’t have carried all those parcels home yourself.
2. It can’t have been Mrs. Mai you saw because she is in Boston.
3. John may work this weekend
4. I should have apologized. That was wrong of me.
5. I needn’t have gone out after all.
6. You can’t have locked the front door. Here is the key.
7. You shouldn’t have left the windows open last night.
8. It must have been Alison who made arrangement. I recognized her voice.
9. He couldn’t possibly have known that his brother was seriously ill.
