问题
选择题
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
答案
答案：C
题目分析：考查时态。根据her voice had been full of life，说明by the time后面使用过去时。Hang up挂断电话。句意：等到我们挂断电话的时候，她的声音充满了活力。故C正确。
点评：时态的考查主要根据上下文的语境和句子的关键词，本题就是根据上下文的语义来辨析使用的。