6.C→ask

7.B→arrive

8.C→is

9.B→would 

10.D→had already left

11.C→should

12.B→have been

13.B→have been making

14.D→get back

15.D→had been

16.A→have

17.C→did

18.C→will be working 

19.A↔have you seen

20.C→can vote

21.A→complained 

22.A→gets

23.D→to be chosen

24.A→had always taken

25.A→don't

26.A→has been writing 

27.C→had already started

28.C→came

29.C→happened

30.D→rang

31.B→have been writting

32.A→goes

33.B→since

34.C→paid

35.A→has gone out

36.B→ends

37.B→was

38.A→while

39.B→discoved 

40,A→have

6:C

7:B

8:C

9:B

10:D

11:C

12:B

13:B

14:D

15:C

16:B

17:D

18:D

19:A

20:C

21:C

22:A

23:C

24:A

25:A

26:D

27:A

28:B

29:A

30:A

31:C

32:C

33:C

34:D

35:B

36:A

37:B

38:C

39:A

40:B