Вставьте подходящий модальный глагол (must / could / ought / may).
1. Einstein speak English when he went to live in the USA?
2. Mary swim when she was three.
3. You be joking. No one buys two Rolls Royces.
4. They be tired. They’ve been travelling all night.
5. He to go to the dentist because he has toothache.
6. I swim quite well when I was five years old.
7. I ride your bicycle, please, Jane?
8. She be Scottish with a surname like McKenzie.
9. At your age you to be earning your living.
10. You to feel some respect for your elders.

1. must
This is because the word "must" expresses strong certainty. We are certain that Einstein had to speak English when he went to live in the USA.

2. could
This is because the word "could" expresses possibility. It is possible that Mary was able to swim when she was three years old.

3. must
This is because the word "must" expresses strong certainty. We are certain that you are joking because no one buys two Rolls Royces.

4. must
This is because the word "must" expresses strong certainty. We are certain that they are tired because they've been traveling all night.

5. may
This is because the word "may" expresses possibility. It is possible that he has to go to the dentist because he has toothache.

6. could
This is because the word "could" expresses possibility. It is possible that I was able to swim quite well when I was five years old.

7. may
This is because the word "may" expresses permission. Jane is asking permission to ride the bicycle.

8. must
This is because the word "must" expresses strong certainty. We are certain that she is Scottish because her surname is McKenzie.

9. ought
This is because the word "ought" expresses obligation. At your age, you ought to be earning your living.

10. ought
This is because the word "ought" expresses obligation. You ought to feel some respect for your elders.