在数据关系模型中,一个关系对应一张二维表,元组对应表中的()。
A 一行
B 一列
C 一格
D 一张表
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Nicotine replacement products are still recommended since they ______.
A. guarantee abstinence from smoking
B. cause little or no harm to the users
C. do not require any prescription
D. help smokers quit thoroughly
We learn from paragraph 1 that______.
A. humility used to co-exist with hostility
B. respecting each other benefits the world
C. everyone demands normal communication
D. everyone can make the world a better place
难建筑施工质量记录就是从建筑施工企业从签订施工合同开始,一直到完成合同规定施工任务和工程或产品质量相关的记录,但不包含来自分承包方的质量记录。()
聚氯乙烯绝缘电力电缆的最小允许弯曲半径是()mm.
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