=>
II/
a/
1. had already sold
2. went
3. had filled/went
4. had never used/didn't know
5. met/hadn't seen
6. didn't want/had already
b/
1. is sleeping
2. is cooking/cooks
3. goes/didn't go
4. are having
5. are building
6. began
7. was/cried
8. didn't see
9. got
10. has studied
11. are playing/am writing
12. watch
13. is writing