When he phoned his friends, they (walk)  in the garden. 2. My mother (cook)  dinner at 6 pm yesterday.
3. The children (play)  on the playground when it suddenly began to rain.
4.  I (play)  the piano when he came home.
5. We (not / cycle)  all morning yesterday.
6. While Bill (work)  in his office, his friends (swim)  in the pool.
7. Mary tried to tell him the truth but he (not/listen) .
8. What (you / do)  at 8 o’clock last night?
9. My grandfather (sit)  in the park all evening.
10.  (Alice\study) English yesterday at 4:00 pm?​

Выделено капсом:

When he phoned his friends, they WERE WALKING  in the garden.

2. My mother WAS COOKING  dinner at 6 pm yesterday.

3. The children WERE PLAYING  on the playground when it suddenly began to rain.

4.  I WAS PLAYING  the piano when he came home.

5. We WEREN'T CYCLING  all morning yesterday.

6. While Bill WAS WORKING  in his office, his friends WERE SWIMMING  in the pool.

7. Mary tried to tell him the truth but he WASN'T LISTENING.

8. What WERE you DOING  at 8 o’clock last night?

9. My grandfather WAS SITTING  in the park all evening.

10.  WAS Alice STUDYING English yesterday at 4:00 pm?​