◎ 题干
Nowhere in nature is aluminum found free,owing to its always       with other elements,most
commonly with oxygen.
[     ]
A.combined
B.being combined
C.combine
D.having combined
◎ 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“Nowhere in nature is aluminum found free,owing to its always with other elements,most commonly with oxygen. [ ]A.combinedB.being combined C.combineD.having …”主要考查了你对  【动名词的被动式】  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。