题目

—Who has made a mess in my room?     —Who else        it but your naughty son?     A. could do        B. could have done    C. did          D. has done 答案： B 解析: 考查情态动词用法。语境表示对过去发生并延续到现在的情况的推测，用could have done表示不肯定的语气。

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