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【单选题】
下列有关三级模式结构和数据独立性的说法，正确的是（ ）。A.
在一个数据库中可以定义多个内模式，可利用不同的内模式来描述特定用户对数据的物理存储需求
B.
外模式是用户与数据库系统的接口，用户可通过外模式来访问数据，在一个数据库中只能定义一个外模式
C.
三级模式结构提供了数据独立性，即当数据的逻辑结构和存储结构发生变化时，应用程序不受影响
D.
数据独立性使得数据的定义和描述与应用程序相分离，简化了数据库应用程序的开发，但增加了用户维护数据的代价
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举一反三
【单选题】The music of a famous Chinese traditional drama Liang Zhu, or Butterfly Lovers was revised a ________ in 1950’s.
A.
Musical
B.
Ballet
C.
Violin Concerto
D.
Piano Concerto
【判断题】The origin of the Double Seventh festival is related to the story of the Butterfly Lovers.
A.
正确
B.
错误
【简答题】How come that lovers are known as the butterfly lovers?
【单选题】How come that the lovers are known as the butterfly lovers?
A.
When both Liang and Zhu were dead, two small butterflies were seen emerging from their grave, flying happily together. Ever after, the two have been known as the butterfly lovers.
B.
They are known as butterfly lovers because of their romantic and moving love stories.
【简答题】在 HTML 中网页要显示的主体内容应放置在( )标签内。
【简答题】How come that the lovers are known as the butterfly lovers? When both Liang and Zhu were dead, two small __________ were seen ___________from their grave, flying ___________together. Even after, the t...
【单选题】What kind of story is The Butterfly Lovers?
A.
A folk story.
B.
A mythology story.
C.
A fable.
【简答题】坚持各民族不分________、历史长短、发展程度高低，一律平等，是立国的根本原则之一。
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