Question

He ________ the exam, but he was too careless

1. A.
   could have passed
2. B.
   couldn’t have passed
3. C.
   must have passed
4. D.
   may have passed

Answer 1

A
试题分析：此处could have passed the exam表示本能通过考试，实际上没有。句意：他本能通过考试的，但是他太粗心了。
考点：考查虚拟语气的用法。