◎ 题干
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The symbolic one-hour switch-off first _____ in Sydney in 2007 has become an annual global event.
A.to hold B.being held C.to be held D.held
◎ 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“.The symbolic one-hour switch-off first _____ in Sydney in 2007 has become an annual global event.A.to hold B.being held C.to be held D.held…”主要考查了你对  【现在分词的被动式】【现在分词】【不定式的被动式】【过去分词】  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。