◎ 题干
By the time he realizes he _____ into a trap, it'll be too late for him to do anything about it.

A. walks
B. walked
C. has walked
D. had walked
◎ 答案
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◎ 解析
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◎ 知识点
    根据魔方格专家分析,试题“By the time he realizes he _____ into a trap, it'll be too late for him to do anything about it. [ ]A. walks B. walked C. has walked D. had walked …”主要考查了你对  【现在完成时】  等知识点的理解和应用能力。关于这些知识点的“档案”,你可以点击相应的链接进行查看和学习。