1, had/was reading

2, were you going/ saw

3, came/was playing

4, wasn't/was calling

5, was buying/met

6, finished/was listening

7, was making/were studying

8, visited/was doing

9, returned/turned

10, was sleeping/were preparing

1. My friends (have) had lunch while Tom (read) was reading magazines online.

2. When you (go)were you going when I (see) saw you in the supermarket?

3. When I (come)came back home, my little son (play) was playing with his elephant.

4. Mr. Tench (not be) wasn't at his office when I (call) was calling him at 10 o'clock last night.

5. Mary (buy) was buying clothes in shops when her mother (meet) met her yesterday.

6. Peter (finish) finished doing his homework, then he (listen) was listening to music

7. As long as my teacher (make) was making the video of Dalat, the students (study) were studying English for next test.

8. An old friend (visit) visited  .my house to meet my mother, she (do) was doing the laundry.

9. Lixian (return) returned home, and (turn)  turned .. on the television.

10. While my boss (sleep) was sleeping in his room, we (prepare) was preparing big party for him.