21£® While ___the dog ,you were careless and it got loose and was hit by a car.

     A. walk   B. walking   C. walked   D. to walk

22. Today we have reached a stage ____ we have almost no rights at all.

     A. when  B. where   C. which   D. that

23. Once she has ___, nothing can change it.

     A. make up her mind     B. made up her minds

     C. made up her mind     D. make up her minds