问题
选择题
He ___________ the test, but he wasn’t careful enough.
A．was able to pass
B．must have passed
C．could have passed
D．might be able to pass
答案
答案：C
考查虚拟语气。句意：他本来能够通过考试，但是他不够细心。“would+have+done”表示对过去事情的假设，表示本来会做而没有做的动作。联系句子意思可知选C。