问题 单项选择题

“学生—选课—课程”数据库中的三个关系:
S(S#,SNAME,SEX,AGE),SC(S#:,C#,GRADE),C(C#,CNAME,TEACHER)它们的主键用下画线标出。

定义一个反映学生姓名及他的平均成绩的视图将使用关系( )。

A.S和C

B.SC和C

C.S和SC

D.S、SC和C

答案

参考答案:C

解析: 该视图要求有学生姓名(在关系S中)、成绩(在关系SC中),所涉及到的关系只有S和SC,所以选项C为正确答案。

阅读理解

You can easily find that your sister or brother is different from you. You live together in the same house and have the same parents, but you have different personalities(性格).

Why? One possible reason is the way your parents treat you.

Firstborn children receive all the attention from their parents. Generally speaking, a firstborn has twice as many photos as any other child has. Parents usually give firstborns more responsibilities (责任)and depend on them to take care of younger brothers and sisters. As a result, firstborns are often responsible, hard-working, and serious. They often want to do well at school and in work. More firstborns became American Presidents, for example George W.Bush, George Washington and Lyndon Baines Johnson, than second or last-borns.

When a second child arrives, parents are more relaxed. The second child has to compete (竞争)with the first-born for parents’ attention and love. These children often choose different sports and hobbies to develop different personalities. They are often outgoing, but can be jealous and get angry easily.

The youngest child is usually the happiest, and has fewer responsibilities and more freedom(自由的). These children do well at school and in work, but have to be creative(创造性的) to get their family’s attention. They are often friendly and cool. Many famous talk-show hosts were born last.

小题1:The underlined word “jealous” means_______ in Chinese

A. 友好的             B. 嫉妒的            C. 快乐的

小题2:The writer thinks that the second-born children are often ______.

A. outgoing but jealous

B. cool and friendly

C. hard-working and serious

小题3:. ______ is usually the happiest in the family according to the passage.

A. The eldest child

B. The second child

C. The youngest child

小题4: We can learn from the passage that ______.

A. the second child is very similar to the firstborn child

B. brothers and sisters usually have the same personalities

C. more firstborns became American presidents than second or last-borns

小题5: The passage is mainly about ______.

A. birth order and personalities

B. children and their parents

C. different children and different work

问答题 简答题