【单选题】
下列表示铜的元素符号是。___
A. Ca;
B. Cd;
C. Cu ;
D. Cr
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答案
C
解析
暂无解析
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下列化合物中哪些全是盐。___
A. NaCL CaCL2 MgCL2;
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空气的垂直与水平运动显著,其物质运动和能量转化,通过水分的三态变化产生一系列物理过程,反映出复杂的天气现象,故什么对地表自然环境影响最大,与人类关系也最密切。___
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关于我国地势特点的说法,正确的是。___
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关于我国地理概况的描述,错误的是。___
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