Ex. A
1. saw
2. was watching
3. went
4. practised
5. were you talking to
6. owned
7. did
8. jumped
9. was working
10. got
11. were playing
12. was passing
Ex. B
1. did you go
2. did you enjoy
3. always tooks
4. were not having
5. went
6. became
7. was working
8. heard
9. was appearing
10. threw
Ex. C
1. had just left
2. gave
3. read
4. made
5. had got
6. had
7. was
8. had got
9. left
10. went
11. got
12. had already begun
13. learned
14. had spoken
15. talked
16. did you decide