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【多选题】
下面关于自然连接和等值连接的叙述中,正确的有A.
自然连接是一种特殊的等值连接
B.
自然连接要求在两个关系中有公共属性,而等值连接不必
C.
两种连接都可以只用笛卡尔积和选择运算导出
D.
自然连接要在结果中去掉重复的属性,而等值连接不必
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【单选题】It can be inferred that Ketek is a medicine which______.
A.
helps lose weight
B.
helps improve memory
C.
treats ear problems
D.
treats liver problems
【多选题】在 Hibernate 中, 下列 关于 Session说法正确的 有
A.
它是线程安全的
B.
它不是线程安全的
C.
它是轻量级的
D.
Session也被称为持久化管理器，它提供了和持久化相关的操作
【单选题】●A user interface can be defined as the combination of hardware and software that helps people and computers (72) with each other. (72)
A.
intercourse
B.
intercommunion
C.
communicate
D.
intercommunicate
【单选题】From the passage it can be seen that employeeship helps one______.
A.
to be more successful in his career
B.
to be more specialized in his field
C.
to solve technical problems
D.
to develop his professional skill
【简答题】It can be inferred from the passage that [A] the 'code of silence' often helps protect guards from violence. [B] the governor's office has decided to give a new life to the prisons. [C] the solution t...
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【单选题】A user interface can be defined as the combination of hardware and software that helps people and computers(72)with each other.
A.
intercourse
B.
intercommunion
C.
communicate
D.
intercommunicate
【单选题】A user interface can be defined as the combination of hardware and software that helps people and computers(70)with each other.
A.
intercourse
B.
intercommunion
C.
communicate
D.
intercommunicate
【单选题】It can be inferred from the directions that this medicine______.
A.
helps you to fall asleep quickly
B.
may be dangerous to small children
C.
cannot be taken if one feels sleepy
D.
should not be taken by children under six
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