问题 填空题

为了把多对多的联系分解成两个一对多联系所建立的“纽带表”中,应该包含两个表的 ______。

答案

参考答案:主关键字或主键

解析:[知识点] 关系数据库:关系模型,关系模式,关系,元组,属性,域,主关键字和外部关键字
[评析] 为了把多对多的联系分解成两个一对多联系所建立的“纽带表”中应包含两个表的主关键字。纽带表不一定需要自己的主关键字,如果需要,应当将它所联系的两个表的主关键字作为组合关键字指定为主关键字。

阅读理解

Without plant, people could not live. We eat plants. We breathe the oxygen(氧气)that plants produce. And we need plants for another reason: we need them for their beauty.

Imagine a world with no plants. Imagine no flowers with their sweet smells, their beautiful colors and their lovely shapes. Imagine when the wind blows, not being able to hear the leaves in the trees or watch the branches sway(摇摆)from side to side.

Everywhere people need the beauty of plants. That is why we have parks full of trees and flowers. That is why people always try to design houses with room for some grass and a garden.

Do you talk to your plants? Do you give them love and attention?

Peter Tompkins and Christopher Bird, writers of a book called THE SECRET LIFE OF PLANTS, tell of an experiment in which two seeds were planted in different places. While the plants were growing, one plant was given love and hopeful ideas. The other plant was given only hopeless ideas. After six months, the loved plant was bigger. Under the earth it had more and longer roots; above the earth, it had a thicker stem (茎) and more leaves.

小题1:According to the passage, which of the following is right?

A.If there are no flowers, there will be no sweet smells.

B.Without plants, we can’t hear the wind.

C.We plant trees to watch the branches sway from side to side.

D.We need plants not only for food and oxygen but also for their beauty.小题2:In the experiment, the plants were________.

A.of different kinds

B.talked to in two different ways

C.both given love and attention

D.grown in the same place小题3:At the end of six months,________.

A.one plant had longer roots than the other and had a thicker stem

B.one plant had longer roots while the other had a thicker stem

C.the plants were of the same size

D.one plant had a thicker stem while the other plant had more leaves小题4:The experiment has proved(证明) that________-.

A.we should talk to plants and give them love

B.without plants people could not live

C.we should grow as many plants as possible

D.plants need plenty of water, sunshine and attention

单项选择题 A2型题