Ответ:

1. b) grow

2. c) will have vanished

3. d) will let

4. b) has never sent

5. c) leaves

6. a) had been finished

7. c) had lost

8. b) have just lost

9. c) have been working

10. d) would buy

11. c) is being pulled down

12. d) had

13. c) had begun

14. a) can

15. b) less

16. b) the

17. c) that

18. b) mine

19. b) less

20. b) on