(单选题)

—He was satisfied with the result, wasn’t he?
—No. It was so difficult that he ______ have passed it.

A.shouldn’t

B.mustn’t

C.couldn’t

D.wouldn’t

参考答案：C

参考解析：

考查情态动词表推测。句意：“他对结果很满意，是吗？”“考试太难了，他不可能通过。”shouldn’t意为“不应该”；mustn’t意为“禁止，不允许”；couldn’t意为“不可能”；wouldn’t意为“不会”。固定结构couldn’t have done意为“不可能做过某事”，此处是对过去事情有把握的否定推测。故选C。

知识点：

—He was satisfied with the result, wasn’t he?—No. It was so difficult that he ______ have passed it.

—He was satisfied with the result, wasn’t he?
—No. It was so difficult that he ______ have passed it.