新概念英語第一冊（美音版）Lesson 128 He can't be …/He must be …

He must be a doctor.

He can't be a doctor.

He must have been a doctor.

He can't have been a doctor.

He may be a doctor.

He may have been a doctor.



He must have gone.

He must have visited.



He must be swimming.

He can't be swimming.

He must have been swimming.

He can't have been swimming.

He may be swimming.

He may have been swimming.



Exercises



He can't be ill.

He must be tired.

It can't be my new hat.

It must be my old one.

She can't be Danish.

She must be Swedish.

He can't be a dentist.

He must be a doctor.

She can't be forty.

She must be fifty.

It can't be the 20th.

It must be the 21st.

He can't be the youngest.

He must be the oldest.

He can't be reading.

He must be sleeping.



Exercises Examples

1 He has to be here at six o'clock.

2 I think he is probably busy.

3 He has to be at the office early tomorrow.

4 I think he is probably sleeping.

5 I think he is probably French.

6 He has to be in France next week.

7 I think he is probably an engineer.

B Examples

1 I don't think so. She can't be Italian. She must be Greek.

2 I don't think so. He can't be English. He must be American.

3 I don't think so. They can't be Canadian. They must be Australian.

7 I don't think so. He can't be twenty-four. He must be thirty.

15 I don't think so. It can't be easy. It must be difficult.

18 I don't think so. He can't be reading. He must be sleeping.

19 I don't think so. They can't be listening to the radio. They must be watching television.

20 I don't think so. She can't be retiring. She must be looking for a new job.