问题 单项选择题

关于分布式数据库,下列描述正确的是()。

A.客户机是分布在不同场地的

B.多个数据库服务器间的数据交互通过客户端程序来实现

C.数据的物理存储分布在不同的服务器上,而用户只关心访问的逻辑结构

D.每个服务器上必须运行相同的DBMS

答案

参考答案:C

解析:

本题考查考生对分布式数据库相关概念的掌握。 分布式数据库将整个数据库分布于不同的服务器上(场地),数据的管理通过分布式数据库管理系统(DDBMS)来管理,用户不需要知道所操作的数据具体存储于哪个场地,只需要知道要访问的数据库逻辑结构,即数据库中的各关系模式。分布式数据库允许不同场地使用不同的DBMS。

阅读理解

A big, mighty(高大的) tree stood in a forest. Its branches(树枝) spread out and its roots (根) went deep in the earth. A lot of people came here to have a rest under it. And a lot of birds stood on its branches to sing and dance. The big tree was very proud all the time.

At the foot of the tree, there was a little plant. The plant was thin, and seemed to be blown down by any of a little wind.

One day, the two neighbors were having a little chat.

“Well, little one,” said the tree to the plant, “why not put your feet deeply in the earth, and raise your head high in the air as I do?”

“I see there is no need to do so,” said the plant with a smile. “In fact, I think I may be safer in this way.”

“Safer?” said the tree. “Are you safer than I am? Do you know how deep my roots are in the earth and how strong my branches are? Who can possibly pull me out by the roots or bow my head to the ground?” And the tree didn’t want to say anything to the weak plant.

But the tree was to regret its words very soon. One evening, a great hurricane(飓风) came. It blew the trees off their roots and almost destroyed the forest completely. It uprooted(将……连根拔起)the mighty tree and blew it away with great force.

When the storm had gone, the villagers living nearby came to check the damage. The mighty tree lay on the ground, but the little plant still stood there.

小题1:Who was the big tree’s neighbor?

A.People.

B.Birds.

C.A little plant.

D.Branches.小题2:Why was the big tree proud before its neighbor?

A.Because a lot of people came to have a rest under it.

B.Because it was tall and thick.

C.Because a lot of birds stood on its branches to sing and dance.

D.All of the above.小题3:Why didn’t the big tree want to say anything to the little plant?

A.Because the big tree was tired.

B.Because the little plant knew less than the big tree.

C.Because the strong wind came.

D.Because the big tree looked down upon(看不起)the little plant.小题4:What did the villagers living nearby see after the hurricane had gone?

A.They saw the forest was flooded.

B.They saw the big tree lying on the ground.

C.They saw the big tree was still mighty.

D.They saw some birds singing on the little plant.小题5: What’s probably the best title of the passage?

A.Trees in the Forest.

B.A Mighty Tree.

C.Trees and Plants.

D.A Clever Plant.

选择题