–I could not start my car this morning due to the cold weather.
--No wonder you were late. You have used mine. I was not using all the morning.
A. should
B. must
C. could
D. might
网友回答
A. should
B. must
(答案→)C. could
D. might
解析：考查情态动词+完成式的用法：句意：--今天早上因为天气太冷，我不能启动汽车。--难怪你迟到了。你本可以用我的，我一早上都没用。Could have done本可以做…却没有做，should have done本应该做却没有做，must have done过去一定做了，might have done过去可能做了。选C。