问题 单项选择题

关系模型是把实体之间的联系用( )表示。

A.二维表格

B.树

C.图

D.E-R图

答案

参考答案:A

解析: 在层次模型中实体间的联系是用树形结构来表示的;在网状模型中实体间的联系可用图来表示:在关系模型中实体间的联系是用二维表格的形式来表示的:信息世界中实体间的联系的实体模型可用E-R图来表示。所以,A是正确答案。

阅读理解

阅读理解。

     In many parts of the world, people live to healthy old ages. What is the secret of their long lives?

     Three things are very important: fresh air, fresh food and a simple way of life. People living in

Himalayas (喜马拉雅山) are famous for their long and healthy lives. They work near their homes in

the clean mountains. They do not have buses, cars or trains. They do not sit all day in busy offices.

They take more exercise and eat less food than people in the cities. They eat vegetables grown by

themselves. They drink milk taken from their own cows. For years, the Hunzas of the Himalayas do

not need doctors, for there is not much illness. They are happy and healthy people.

1. Which is NOT the life of the people living in Himalayas?

A. They work near their homes in the clean mountains.

B. They take more exercise and eat more food than people in the cities.

C. They eat vegetables grown by themselves.

D. They drink milk taken from their own cows.

2. Which one is NOT true about the people living in Himalayas?

A. They live in a simple life in the mountains.

B. They grow vegetables and milk cows themselves.

C. When they're ill, they do not go to see the doctors.

D. They do not sit all day in busy offices.

3. Which is NOT the secret of long life?

A. Fresh air.

B. Fresh food.

C. A simple way of life.

D. A simple way of eating.

4. What are the Hunzas famous for?

A. Vegetables.

B. Milk.

C. Food.

D. Their long and healthy lives.

5. They do not need doctors, for______.

A. the doctors are not good

B. there is not much illness

C. there is no illness

D. they are happy

单项选择题