问题 单项选择题

下列关于万兆以太网的描述中,正确的是( )。

A.应考虑介质访问控制问题

B.可以使用屏蔽双绞线

C.只定义了局域网物理层标准

D.没有改变以太网的帧格式

答案

参考答案:D

解析: 万兆以太网是10Gbps以太网,它在物理层只使用光纤,和其他以太网使用相同的帧格式,它以全双工方式工作,不需要解决介质争用问题。因为物理层使用光纤通道技术,所以需要制定局域网和广域网两种物理层标准。

阅读理解

任务型阅读。阅读下面的短文,并完成短文后的任务。

    Waste can be seen everywhere in the school. Some students ask for more food than they can eat and

others often forget to turn off the lights when they leave the classroom. They say they can afford these

things. But I don't agree with them.

    Waste can bring a lot of problems. Although China is rich in some resources (资源), we are short of

others, for example, fresh water. It is reported that we will have no coal or oil to use in 100 years. So if

we go on wasting our resources, what can we use in the future and where can we move? Think about it.

(1) I think we should say no to the students who waste things every day. Everybody should stop wasting

as soon as possible.

    In our everyday life, we can do many things to prevent (阻止) waste from happening, for example,

turn off the water taps when we finish washing, turn off the lights when we leave the classroom, try not

to order more food than we need, and so on. Little by little, everything will be changed. (2) Waste can be

stopped one day, if we do our best.

任务1:根据要求答题。(请注意问题后的词数要求)

1. List the wastes mentioned in the first passage: (within 15 words)

    _________________________________________________________

2. What problems can waste bring? (within 20 words)

(1) _________________________________________________________

(2) _________________________________________________________

任务2:将短文中划线的句子翻译成汉语。

3. __________________________________________________________

4. __________________________________________________________

任务3:请给短文拟一个适当的标题:(within 5 words)

5. __________________________________________________________

单项选择题