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【简答题】
按条件f对关系R进行选择，其关系代数表达式是 A．R|×|R C．σf(R) D．πf(R)
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举一反三
【单选题】We have to cite when we use the following materials EXCEPT_____.
A.
Statistics
B.
Common opinions
C.
Theories and facts
D.
Images, graphs and tables
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【单选题】因 Q P = Δ H , Q V = Δ U ,所以 Q P 与 Q V 都是状态函数。
A.
对
B.
Δ H, Δ U是状态函数，Qp和Qv不是
C.
以上没有状态函数
D.
H，U是状态函数， Q P 与 Q V 不是
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【判断题】因为 Qp = Δ H , Q V = Δ U ,而焓与热力学能是状态函数,所以 Qp 与 QV 也是状态函数。
A.
正确
B.
错误
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【判断题】When we cite data from a study, we need to give out a detailed description of a whole set of data.
A.
正确
B.
错误
查看完整题目与答案
【判断题】When we cite data from a study, we need to give out the source or the location, so that the audience would know where to get more detail for that data.
A.
正确
B.
错误
查看完整题目与答案
【单选题】数据库的设计过程可以分为需求分析、概念设计、逻辑设计、物理设计4个阶段，概念设计阶段得到的结果是______。
A.
数据字典描述的数据需求
B.
E-R图表示的概念模型
C.
某个DBMS所支持的数据模型
D.
包括存储结构和存取方法的物理结构
查看完整题目与答案
【判断题】When we cite data from a study, we need to present the original table or figure together with a textual description.
A.
正确
B.
错误
查看完整题目与答案
【判断题】When we cite data from a study, we usually interpret the meaning of the data instead of just giving out the data itself.
A.
正确
B.
错误
查看完整题目与答案
【单选题】When should we cite?
A.
Whenever we present opinions that are not dependent on others’ work.
B.
Whenever we present statements that are not dependent on others’ work.
C.
Whenever an idea or a statement we present is dependent on others’ work.
D.
Whenever an idea or a statement we present is new and unique.
查看完整题目与答案
【多选题】when we cite sources orally, which should be identified?
A.
the book, magazine, newspaper, or Web document you are citing
B.
the author or sponsoing organization of the document
C.
the author's qualifications with regard to the topic
D.
the date on which the document was published, posted, or updated
查看完整题目与答案
相关题目：
【单选题】We have to cite when we use the following materials EXCEPT_____.
A.
Statistics
B.
Common opinions
C.
Theories and facts
D.
Images, graphs and tables
查看完整题目与答案
【单选题】因 Q P = Δ H , Q V = Δ U ,所以 Q P 与 Q V 都是状态函数。
A.
对
B.
Δ H, Δ U是状态函数，Qp和Qv不是
C.
以上没有状态函数
D.
H，U是状态函数， Q P 与 Q V 不是
查看完整题目与答案
【判断题】因为 Qp = Δ H , Q V = Δ U ,而焓与热力学能是状态函数,所以 Qp 与 QV 也是状态函数。
A.
正确
B.
错误
查看完整题目与答案
【判断题】When we cite data from a study, we need to give out a detailed description of a whole set of data.
A.
正确
B.
错误
查看完整题目与答案
【判断题】When we cite data from a study, we need to give out the source or the location, so that the audience would know where to get more detail for that data.
A.
正确
B.
错误
查看完整题目与答案
【单选题】数据库的设计过程可以分为需求分析、概念设计、逻辑设计、物理设计4个阶段，概念设计阶段得到的结果是______。
A.
数据字典描述的数据需求
B.
E-R图表示的概念模型
C.
某个DBMS所支持的数据模型
D.
包括存储结构和存取方法的物理结构
查看完整题目与答案
【判断题】When we cite data from a study, we need to present the original table or figure together with a textual description.
A.
正确
B.
错误
查看完整题目与答案
【判断题】When we cite data from a study, we usually interpret the meaning of the data instead of just giving out the data itself.
A.
正确
B.
错误
查看完整题目与答案
【单选题】When should we cite?
A.
Whenever we present opinions that are not dependent on others’ work.
B.
Whenever we present statements that are not dependent on others’ work.
C.
Whenever an idea or a statement we present is dependent on others’ work.
D.
Whenever an idea or a statement we present is new and unique.
查看完整题目与答案
【多选题】when we cite sources orally, which should be identified?
A.
the book, magazine, newspaper, or Web document you are citing
B.
the author or sponsoing organization of the document
C.
the author's qualifications with regard to the topic
D.
the date on which the document was published, posted, or updated
查看完整题目与答案