问题 单项选择题

在 ISO/OSI 参考模型中,网络层的主要功能是______。

A.组织两个会话进程之间的通信,并管理数据的交换

B.数据格式变换、数据加密与解密、数据压缩与恢复

C.路由选择、拥塞控制与网络互连

D.确定进程之间通信的性质,以满足用户的需要

答案

参考答案:C

解析:网络层的功能是在信源和信宿之间建立逻辑链路,为报文或报文分组的传递选择合适的路由以实现网络互联。为进行路由选择,要选择合适的路由选择算法,并针对网络情况实现拥塞控制。

阅读理解

阅读理解。

     Two years ago my husband bought me a bicycle. If you live in a city, it is often faster than a car and

you don't have to worry about parking (停车). You can leave it anywhere. As it has a seat at the back and

a basket at the front, I can take my daughter to school, to the library, to the shops, to anywhere.

     I use it most in summer when the weather is warm and dry. It can be very unpleasant (不愉快) in winter

when it is cold and the rain is heavy.

    Of course, you must be careful on a bicycle. Accidents are not the only problems. One day I went

shopping and came back late. I found my front wheel missing. It was a long walk to the bicycle shop. Now

I have three strong locks.

    My husband uses my bicycle sometimes for short journeys. He says it is better than waiting for a bus.

He still uses his car for longer journeys. I think that all this sitting down is making him fat and lazy. On my

bike I get a lot of exercises and fresh (新鲜的) air, and this makes me feel a lot younger.

1. In a city, a bike is better than a car because _______.

A. it is much cheaper

B. it is often faster in a city

C. you don't have to worry about parking a bike

D. Both B and C

2. Why doesn't the writer like to use the bike in winter?

A. Because it is cold in winter and she would be wet when in rains hard.

B. Because she has to be very careful.

C. Because there are many accidents.

D. All of the above.

3. Which of the following is not true?

A. The writer is a mother.

B. The wheels of her bike were broken.

C. She often goes to school with her little daughter.

D. Her husband uses her bike at times.

4. Her husband uses her bike for _______.

A. long journeys

B. short journeys

C. going to work

D. going to the library

5. What's the best title (题目) for this passage?

A. My Bicycle

B. Bicycle in the city

C. A Present From My Husband

D. A bicycle

选择题