Underline the incorrect modal verb and replace it with a more suitable one. Sometimes more than one answer is possible. (Gạch dưới động từ khuyết thiếu và thay thế bằng từ phù hợp hơn. Có thể có nhiều hơn một câu trả lời đúng.)

1. They mustn’t have seen Max – he’s away on holiday.

2. Joe knew about the strike. He must have warned me!

3. I couldn’t have yawned when Tim told that story. It was a bit rude of me.

4. It was so noisy. It’s possible he ought not to have heard us.

5. I emailed Erin a week ago, so she can’t have read it by now.