Someone called me up in the middle of the night ,but they hung up __I could answer the phone.

问题描述:

Someone called me up in the middle of the night ,but they hung up __I could answer the phone.
A.asB.before
答案是B,我感觉B的话hung up 要用过去完成时啊
感觉A满对的正巧我拿起电话时对方挂电话了

过去完成时代表过去的过去,这里说的是midnight.
as用作当、、、、的时候时,主句和从句的动作是同时发生的,只有延续的含义.你的第二句话看不大懂额,能不能举个例子