问题 单项选择题

在下述关于数据库系统的叙述中,正确的是 ______。

A.数据库中只存在数据项之间的联系

B.数据库的数据项之间和记录之间都存在联系

C.数据库的数据项之间无联系,记录之间存在联系

D.数据库的数据项之间和记录之间都不存在联系

答案

参考答案:B

解析:[知识点] 数据库的基本概念
[评析] 用二维表结构来表示实体以及实体之间联系的模型称为关系模型。关系数据模型是以关系数学理论为基础的,在关系模型中,操作的对象和结果都是二维表,这种二维表就是关系。关系模型与层次型、网状型的本质区别在于数据描述的一致性,模型概念单一。在关系型数据库中,每一个关系都是一个二维表,无论实体本身还是实体间的联系均用称为“关系”的二维表来表示,使得描述实体的数据本身能够自然地反映它们之间的联系。而传统的层次和网状模型数据库是使用链接指针来存储和体现联系的。

阅读理解

Most kids hate doing housework. However, not all hope is lost. There are some things that you can do to get your kids to help you clean your house. If you are struggling with the chores (家务)and need your kids to help you, take a look at some of the creative ways in this article.

If you are dealing with older kids, you may want to try the allowance deal. You can give your kids a list of chores that need to be done each week. If they complete these chores, you can give them some money. You can also break the list down and tell them they will get so much for each chore that is finished. Older kids , who like to do things on weekends or buy things like video games, will work hard to complete their chores and earn their money. This is also teaching them responsibility. This is teaching them that they must work for what they want.

If you are dealing with younger kids, you may want to go with the rewards chart(奖励图表). This is where you design a chart and list their chores on the chart. For each chore they complete, you can put a red flower beside it. For the rewards, you canalso do a number of things ,such as going to the park, going out to eat, buying a DVD or something similar. The rewards would be up to you because you know what your kids like.

For real small kids, you can turn it into a game. When kids were much younger, you can teach them to dance around and sing as you cleaned. The kids loved it and would do a wonderful job at picking up their toys. So, consider turning cleaning into a game for the real small kids.

小题1:What does the underlined word “allowance” in Paraph 2 mean ?

A.Good words given by parents

B.Business that needs studying

C.Explanation of responsibility

D.Small change given by parents小题2:Why can we put a red flower beside the chore on a chart?

A.To know what your kids like.

B.To know how many chores the kids have done.

C.To encourage younger kids to do more chores.

D.To go out to eat or do something similar they like.小题3: What can we know from this article?

A.Kids should help parents do more chores.

B.Parents should teach kids how to do housework.

C.The more chores kids do, the more they love their parents.

D.Creative methods can be helpful for parents to get their kids to do housework.

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