◎ 题干
By the time Jack returned home from England,his son ________ from college.(2011·辽宁)
A.graduated B.has graduated
C.had been graduating D.had graduated
◎ 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 Jack returned home from England,his son ________ from college.(2011·辽宁)A.graduatedB.has graduatedC.had been graduatingD.had graduated…”主要考查了你对  【过去完成时】【过去完成时的被动语态】  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。