问题 单项选择题

以下网络中,属于城域网的是

A.公用分组交换网(X. 25)

B.光纤分布式数字接口FDDI

C.异步传输模式ATM

D.B—ISDN

答案

参考答案:B

解析: 城域网设计的目标是要满足几十公里范围内的大量企业、机关、公司的多个局域网互联的需求,以实现大量用户之间的数据、语音、图形与视频等多种信息的传输功能。
早期的城域网主要以FDDI作为主干网,目前的城域网已广泛使用IP路由交换机或ATM交换机,从而具有广域网的许多技术特征。光纤分布式数字接口FDDI是以光纤作为传输介质的高速环网,传输速率为100Mb/s,通常用做连接多个局域网的主干网。FDDI具有高数据传输率、高抗电磁干扰、信号传输衰减小等特点,且覆盖地理范围大、负载能力强、具有实时和优先访问权,能实现数据、语音、图像的综合服务。

阅读理解

阅读理解。

     Once there was a king. He never ate a meal without fish. But one day there was a big storm (风暴) and

the fishermen were not able to go out to catch fish, so the king had no breakfast and no lunch. Then he

ordered his servants (仆人) to tell everyone in his country that if anyone brought him a fish, he would give

him anything he asked for.

     At last, a fisherman caught a big fish and hurried to the king's palace with it. But the king's prime minister

(宰相) stopped him and said, if the fisherman did not promise (答应) to give him half of whatever the king

gave him for the fish. He would not let the fisherman in.

     The king was very happy when he saw the fish. He said to the fisherman,"Now, what do you want for

your fish?"

      "I want you to beat (打) me twenty-four times" said the fisherman.

      The king was very surprised, and at last he said, "I promised to give you whatever you wanted, and I

think that I must keep my promise." So he began to beat the fisherman softly.

      "No," said the fisherman, "beat me as hard as you can!"

      After the king had beaten him twelve times, the fisherman jumped away and said, "That's enough for me.

I promised the other twelve to your prime minister."

      Again the king was very surprised, but the prime minister had to admit (承认) that the fisherman was

right. The king not only gave him the twelve beatings, but also said, "You will not be my prime minister."

1. The king           . [ ]

A. never ate fish

B. liked to eat fish very much

C. never ate fish without a meal

D. never ate a meal

2. The king's prime minister stopped the fisherman because           . [ ]

A. he didn't want the king to eat fish

B. the fisherman had a fish in hand

C. he wanted to get half of the fisherman's reward (报酬)

D. the fisherman walked fast

3. Why did the fisherman want the king to beat him? Because           . [ ]

A. he knew he was wrong

B. the king had no meal for days

C. he wanted the prime minister to be beaten, too

D. he was afraid of the prime minister

4. In fact the fisherman was beaten           . [ ]

A. twenty-four times

B. twelve times

C. forty-eight times

D. softly

5. At first, why did the king beat the fisherman softly? [ ]

A. Because the king was too weak.

B. Because he didn't want to beat the man.

C. Because the fisherman was old.

D. Because he knew he would beat the prime minister, too.

选择题