在数据库设计中,用E-R图来描述信息结构但不涉及信息在计算机中的表示,它是数据库设计的______阶段。
A.需求分析
B.概念设计
C.逻辑设计
D.物理设计
参考答案:B
— Have you seen Tony recently?
— No, but I _____ dinner with him on Sunday. [ ]
A. would have
B. have had
C. have been having
D. am having
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