must have + P2 : chắc chắn đã...
can't have + P2: chắc hẳn đã không...
1. We must have been asleep.
2. He can't have seen me.
3. It must have been expensive.
4. They must have gone away.
5. He must have left the restaurant last night.
6. The exam can't have been very difficult.
7. He must have listened to our conversation.
8. He can't have understood what I said.
9. We must have forgotten to turn it off.
10. The driver can't have seen the red light.