16. I have been playing
17. I will have been working
18. will have delivered
19. have been practicing
20.had done
1. had been learning
2 . is repairing/has been doing
3. will have been reading
4. have you been sitting/have you been writing/have been waiting
5.works/will have been working
6. has been walking /hasn`t come
7. have been saving/ will have had
8. have you known/ have known
9. had been experimenting
10. is snowing/has been snowing
11.studies/will have been studying
12. were you doing/was preparing/had been preparing
