Напишите следующие предложения в прошедшем и будущем времени:
1. I must do my exercises.
2. He must be at the Institute at 9 o'clock.
3. You must learn the story by heart.
4. We must walk fast to get to the station in time.
5. She must do it at once.
6. I must wait for him.

1. I had to do .,.; I shall have to do ... .
2. He had to be ...; He will have to be ... .
3. Yau had to learn ...; You will have to learn ... .
4. We had to walk ...; We shall have to walk ... .
5. She had to do ...; She will have to do ... .
6. I had to wait ...; I shall have to wait ... .