问题 填空题

如果一个工人可管理多个设备,而一个设备只被一个工人管理,则实体“工人”与实体“设备”之间存在()关系。

答案

参考答案:一对多(或1对多、或1:M、或1:N,其中M、N大小写均可)

解析:

实体之间的联系可以归结为三类:一对一的联系,一对多的联系,多对多的联系。设有两个实体集E1和E2,如果E2中的每一个实体与E1中的任意个实体(包括零个)有联系,而E1中的每一个实体最多与E2中的一个实体有联系,则称这样的联系为"从E2到E1的一对多的联系",通常表示为"1:n的联系"。由此可见,工人和设备之间是一对多关系。

阅读理解

阅读理解

     The home service industry in Beijing is expected to become more attractive both as a job and as an

industry.

     Sources at the Beijing People's Political Consultative Conference said resistance to home service

work is melting away from minds of the city's laidoff workers. The Conference suggested the

establishment of municipal (市政的) centers which supervise property management, household mending

and installation, and house keeping services. Modern city life is creating a need for home services. This

will create job opportunities for laidoff workers, said vice director of the Social Judicial Committee of

the Conference.

     Beijing residents have long desired a home service industry. The demand is expected to drive new

economic growth. There are few high quality home help services in Beijing and customers are always

complaining.

     In the past, few laidoff workers worked as home helpers, jobs largely taken by young women from

the countryside. At the same time, some city residents have not felt safe trusting rural girls with modern

household machines or with their small children. Many people would pay more for reliable house keepers who are more familiar with city life, but they have had no way of getting one, even though the city is home

to thousands of laidoff workers.

     By the end of June this year, there were 30,600 jobless workers in the city. Most of them are women

in their 40's, who are not blessed with particular skills and who have had their work ethics shaped by the

planned economy. Many of them were at a loss when they first realized they had lost their jobs and a

way of life they had got used to for decades.

     They never imagined being laidoff by state; they never considered other kinds of employment. For

them, the private sector (领域) meant taking risks; housekeeping implied lower social status. Gao

yunfang, 44, is a pioneer who is breaking the ice. She sells the Beijing Morning Post in the morning, and

works at two households in the afternoon. She earns 1,000 yuan per month.

     So she no longer worries about her daughter's tuition at a university in Shanghai.

1. What is talked about in the passage?

A. Home service.  

B. Modern city life.  

C. Laidoff workers.  

D. Social status.

2. Why didn't the laidoff workers like to do home services in the past?

A. Low salary.            

B. Lower social status.  

C. Dirty working condition.  

D. Too much extra work.

3. Why were many laidoff workers at a loss?

A. Because they didn't get used to the new way of life.

B. Because they are too old to find a new job.

C. Because they dislike being laid off.

D. Because they think they lost their social status.

3. In which ways is home service industry good for our society?

A. It meets the needs of modern life.  

B. It provides work opportunities for the laidoff worker

C. It is a new industry.            

D. A and B.

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