While I ( ) the bus,it started to rain.A.was waiting for B.waited for C.am waiting for

问题描述:

While I ( ) the bus,it started to rain.A.was waiting for B.waited for C.am waiting for

A .当我在等车的时候 ,天开始下雨.while 后接doing,表示当时正在干嘛干嘛