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【简答题】
在数据模型中,常见的数据模型有 、 、 和 ;基本层次数据模型用于描述 实体(型)。数据库管理系统的类型由它支持的 决定。可能有多个根结点,每个非根结点可能有多个父结点,这是 数据模型;有且仅有一个根结点,而每个非根结点有且仅有一个父结点,这是 数据模型。在关系模型中,用二维表描述 ;表中每行数据描述 ;通过 能分析出同类实体之间的联系,通过 能分析出不同类实体之间的联系。
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【单选题】This is the best way I could think of ______ him ______ computer games.
A.
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B.
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C.
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D.
stopping; to play
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