Раскройте скобки, употребляя глаголы в Past Simple или Past Continuous. 1. At this time yesterday I (to sit) at the theatre. 2. He (to come) back to St. Petersburg on the 15th of January. 3. I (to go) to the institute when I (to see) him. 4. At this time yesterday we (to have) dinner. 5. He (to write) a letter when I (to come) in. 6. He (to make) a report when I (to leave) the meeting. 7. Yesterday he (to write) a letter to his friend. 8. When I (to look) at them, they (to smile) at me. 9. What you (to do) at six o'clock yesterday? 10. I (to go) to bed at half past eleven. 11. Yesterday the lesson (to begin) at nine o'clock. 12. The cat (to take) a piece of fish 'and then (to run) away. 13. He (to read) a newspaper when I (to come) in. 14. Yesterday I (to get) up at seven o'clock. 15. The train (to start) at fifteen minutes to ten. 16. He (to put) on his coat and cap, (to open) the door and (to go) out.

Вот правильные формы (Past Simple или Past Continuous):

1. At this time yesterday I was sitting at the theatre.

2. He came back to St. Petersburg on the 15th of January.

3. I was going to the institute when I saw him.

4. At this time yesterday we were having dinner.

5. He was writing a letter when I came in.

6. He was making a report when I left the meeting.

7. Yesterday he wrote a letter to his friend.

8. When I looked at them, they were smiling at me.

9. What were you doing at six o'clock yesterday?

10. I went to bed at half past eleven.

11. Yesterday the lesson began at nine o'clock.

12. The cat took a piece of fish and then ran away.

13. He was reading a newspaper when I came in.

14. Yesterday I got up at seven o'clock.

15. The train started at fifteen minutes to ten.

16. He put on his coat and cap, opened the door and went out.

Почему так: Past Continuous — длительное действие в конкретный момент в прошлом или фон (был в процессе), Past Simple — завершённое разовое действие или цепочка действий, а также «вклинивающееся» событие, которое прерывает длительный процесс.