◎ 题干
No one knows exactly ______ this important discovery was made.
A.that   B.that how   C.what   D.when
◎ 答案
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◎ 解析
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◎ 知识点
    根据n多题专家分析,试题“No one knows exactly ______ this important discovery was made.A.thatB.that how C.what D.when…”主要考查了你对  【并列连词】【从属连词】  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。