问题 单项选择题

下面关于模式和实例的说法中,不正确的是

A.模式的一个具体值称为模式的一个实例

B.一个模式对应着一个唯一的实例

C.模式是相对稳定的,实例是相对变动的

D.模式反映的是数据的结构及其联系

答案

参考答案:B

解析: 模式是数据库中全体数据的逻辑结构和特征的描述,它仅仅涉及到型的描述,不涉及到具体的值。模式的一个具体值称为模式的一个实例。同一个模式可以有很多实例。模式是相对稳定的,而实例是相对变动的,因此数据库中的数据是在不断更新的。模式反映的是数据的结构及其联系,实例反映的是数据库某一时刻的状态。

阅读理解

I won’t forget her advice

I had a very special teacher in high school many years ago. Her husband died of a heart attack. About a week after his death, she shared some of her insights(见解)with us.

The class was nearly over. She said, “Before class is over, I would like to share with all of you an important thought.”

“Each of us is put here on Earth to learn, share, love, enjoy and give all by ourselves. We must make the best of every single day.”

Her eyes were beginning to water and she went on, “So I would like you all to make me a promise. From now on, on your way to school, or on your way home, find something beautiful to notice. It doesn’t have to be something you see — it could be a nice smell — perhaps of freshly baked bread, or it could be the sound of the breeze slightly blowing the leaves in the trees.”

“Please look for these things, and love them. For, although it may seem common, these things are the stuff(素材)of life. They are the little things we are put here on Earth to enjoy. They are the things we often take for granted. We must make it a point to notice them, for at any time it can all be taken away.”

The class was completely quiet. We picked up our books and went out of the room silently. That afternoon, I noticed more things on my way home from school than I had that whole term.

I usually think of that teacher and try to enjoy all of those things that we sometimes overlook (忽略).

Take notice of something special you see during your lunch hour today. Walk barefoot along the beach at sunset. For as we get older, it is not the things we did that we regret(后悔), but the things we didn’t do.

小题1:What happened to the teacher’s husband?

A.He was ill.

B.He died of a heart attack.

C.He made a promise.

D.He became a teacher, too.小题2:The high school teacher shared her insights with her students ____________.

A.on her way to school

B.on her way home

C.at the beginning of class

D.at the end of class小题3:The underlined word “breeze” (in Paragraph 4) means ____________?

A.colourful cloud

B.white snow

C.light wind

D.heavy rain小题4:What is the teacher’s advice?

A.We should love life and enjoy things around us.

B.We should share our important thoughts with others.

C.We should never feel sorry for what we have done.

D.We should do importand things and overlook little ones.

选择题