When I talked with my grandma on the phone, she sounded weak, but by the time we

When I talked with my grandma on the phone, she sounded weak, but by the time we ___ up, her voice had been full of life.   

A. were hanging  B. had hung    C. hung   D. would hang  

试题答案

C

解析:

考查时态。By the time 后的从句中多用一般现在时和一般过去时。根据该题的语境可以断定答案为:C.