Why on earth didn’t you answer the door?I’m terribly sorry but the telephone to

问题补充：

--- Why on earth didn’t you answer the door?

--- I’m terribly sorry, but the telephone , too.

A. is ringing

B. was ringing

C. rang

D. was about to ring

答案：

A. is ringing

(答案→)B. was ringing

C. rang

D. was about to ring

解析：表示过去某一时间正在进行的动作，用过去进行时，故选B。