Question

—Mary’s got crazy and has been sent to the mental hospital. Did you tell her boss about that?
—Yes, but I _______her husband first.  

1. A.
   can have told
2. B.
   should have told
3. C.
   need have told
4. D.
   must have told

Answer 1

B
试题分析：考查情态动词用法。Can have done可能做了某事；Should have done本应该做某事，实际上却未做；need have done本需要做某事，实际上却未做；must have done一定做了某事；句意：—Mary疯掉了，已经被送到了精神病医院。你把这件事情告诉她的老板了吗?—是的。但是我本应该先告诉他丈夫的。BC两项是虚拟语气，表示对过去的虚拟。AD两项表示对过去情况的推测。
考点：考查情态动词用法。
点评：“情态动词+have done”可以表示对过去情况的推测也可以表示对过去情况的虚拟。如Can have done可能做了某事；must have done一定做了某事；这两个词组不是对过去情况的推测；Should have done本应该做某事，实际上却未做；need have done本需要做某事，实际上却未做；表示对过去情况的虚拟。