Ответ:

1. We were writing dictation at 10 o'clock yesterday.

2. They were having lunch at half past 7.

3. They were having lunch at this time yesterday. I was washing dishes in the kitchen.

4. She was talking with her teacher for 20 minutes.

5. At this time last Tuesday we were returning from the supermarket.

6. Was he waiting for you at 7 o'clock yesterday? Yes, he was.

7. Were you working in the garden yesterday afternoon? – No, we were visiting aunt.

8. Was he sleeping at 2 o'clock yesterday? No, he was learning a poem.

Объяснение:

прошу заметить, во втором номере – не ошибка, там должно быть семь по правилу.