26．No one could answer the question , ____ ____ ?

25．Somebody called me at four yesterday afternoon, ____ ____ ?

24．She won't go to bed until she finishes her work , ____ ____ ?

23．He told us to do that but we don't know why , ____ ____ ?

22．He said Mary could made the model plane , ____ ____ ?

21．There's a police car over there , ____ ____ ?

20．He needs our help, ____ ____ ?

19．Everything has been finished, ____ ____ ?

18．We'd better help her, ____ ____ ?

17．They'll be on duty next Monday, ____ ____ ?