问题补充:
Her brother while he his big horse and had his leg broken.
A. fell; was riding
B. fell; ride
C. had fallen; was riding
D. had fell; rode
答案:
(答案→)A. fell; was riding
B. fell; ride
C. had fallen; was riding
D. had fell; rode
解析:while he was riding给出一个表示一段时间的状语,主句表示在此期间发生的动作行为.