Ответ:

1. b  ) have been

2. a  ) went

3. c  ) had seen

4. c  ) was reading

5. a  ) won't ride

6. c  ) is being built

7. a  ) stops

8. b  ) provides

9. c  ) is blamed

10. a)   don't know

11. d  ) are you getting on

12. d  ) will you arrive

13. b  ) have to

14. b  ) had

15. d  ) the best

16. b  ) less

17. a )  a

18. a  ) -

19. d  ) -

20. b) at