15 Complete the sentences using the most suitable modal verbs: must, have to.
1. You go to bed immediately. It's midnight already. 2. You ...
feed the dog tonight. I'll be out. 3. If you want to be a pupil of the
school specializing in science, you will ... improve your maths.
1. You are coughing too badly. You really ... stop smoking and you
definitely ... not stay too long in the cold, Mr Gordon. 5. I have put
on weight. I really ... stop eating so much cake and chocolate. 6. The
accident was
your fault. You ... be more careful in future.
you wear these tight trousers whenever your granny comes?
She always gets furious when she sees you in them. 8. You ... phone
Alice about the meeting tomorrow. Boris has already explained every-
thing to her. 9. Clara ... go shopping yesterday. None of the family
could do it except her. 10. ... you always be talking in my class,
Charlie?
7.
..

1. You must go to bed immediately. It's midnight already.
- The speaker is giving a strong recommendation to go to bed immediately because it is already midnight. "Must" is used to express strong obligation or necessity.

2. You have to feed the dog tonight. I'll be out.
- The speaker is stating a requirement or obligation for the person to feed the dog since they will be out. "Have to" is used to express a general necessity or requirement.

3. If you want to be a pupil of the school specializing in science, you will have to improve your maths.
- The speaker is stating a requirement or condition for the person to improve their math skills if they want to be accepted into a science-specialized school. "Will have to" is used to express a future obligation or requirement.

4. You really must stop smoking and you definitely must not stay too long in the cold, Mr Gordon.
- The speaker is strongly advising Mr. Gordon to stop smoking and not to stay in the cold for too long. "Must" is used to emphasize the necessity of these actions.

5. I have put on weight. I really have to stop eating so much cake and chocolate.
- The speaker is expressing a personal obligation or necessity to stop eating excessive amounts of cake and chocolate due to weight gain. "Have to" is used to express a general necessity or requirement.

6. The accident was your fault. You must be more careful in the future.
- The speaker is assigning blame to the person for the accident and insisting that they need to be more cautious in the future. "Must" is used to emphasize the strong obligation for the person to be more careful.

7. Will you wear these tight trousers whenever your granny comes? She always gets furious when she sees you in them.
- The implication here is that the person should not wear the tight trousers when their granny is present because she becomes angry when she sees them in them. There is no specific modal verb used in this sentence, but the question implies a recommendation not to wear the trousers.

8. You have to phone Alice about the meeting tomorrow. Boris has already explained everything to her.
- The speaker is stating an obligation for the person to call Alice about the meeting because Boris has already explained everything to her. "Have to" is used to express a general necessity or requirement.

9. Clara had to go shopping yesterday. None of the family could do it except her.
- The speaker is stating that Clara was obligated to go shopping yesterday because no one else in the family could do it. "Had to" is used to express a past necessity or requirement.

10. Must you always be talking in my class, Charlie?
- The speaker is expressing annoyance or frustration with Charlie for constantly talking in their class. "Must" is used to emphasize the strong obligation for Charlie to stop talking in class.

Therefore, the appropriate modal verb would be chosen based on the level of obligation or necessity implied in each sentence. "Must" is used for stronger obligations, while "have to" is used for general requirements or obligations.