Ответ:

13)had

14)Did you stay?

15)stayed

16)were

17)went

18)What did you study?

19)didn't like

20)Why didn't you like it?

21)was

22)left

23)took

24)was

25)When was this happen?

26)arrived

27)went

28)Did you see the person take your bag?

29)came

30)wasn't

31)Did you have anything valuable in your bag?