题目

With her health ____________________, she had to quit the job she loved.      A. broken down       B. broke down      C. having broken down      D to break down 答案：C 解析: 略原电池是将 能转化为 能．其中，电子流出的一极是原电池的 极，电子流入的一极是原电池的 极，原电池的负极发生 反应．