He fell off the bike .A. while he rodeB. while he was ridingC. while he is ridingD. while

问题补充：

He fell off the bike .

A. while he rode

B. while he was riding

C. while he is riding

D. while on bike

答案：

A. while he rode

(答案→)B. while he was riding

C. while he is riding

D. while on bike

解析：本题主要考查的是while 引导的时间状语从句，一般而言，主句的动作发生在从句之中，故从句要用进行时态，故选B