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问题 单项选择题

在IEEE 802系统协议中描述逻辑链路控制子层(LLC) 的功能、特性和协议的是 _______。

A．IEEE 802.5

B．IEEE 802.4

C．IEEE802.2

D．IEEE 802.3

答案

参考答案：C

解析： IEEE 802委员会为局域网制定了一系列的标准，统称为IEEE 802标准。其中IEEE 802．2标准定义了逻辑链路控制子层的功能与服务。

阅读理解

阅读理解。

     Tom is a little boy, and he's only seven years old .One day he goes to the cinema by himself. It is the

first time for him to do that. He buys a ticket and goes in. But after two or three minutes he comes out

and buys a ticket again. Two or three minutes after that, he comes out and asks for another ticket. The

girl selling the tickets asks him, "Why do you buy so many tickets? How many friends do you meet?"

Tom answers, "No, I have no friends with me. But the old man always stops(拦住)me at the door and

tears up (撕掉) my ticket."

1. How old is Tom?

A. Eleven

B. Seven      

C. Seventeen

D. Four

2. It is _______ for Tom to go to the cinema.

A. the first time

B. the second time  

C. the third time

D. the last time

3. Tom buys _______ before the girl asks him.

A. one ticket

B. five tickets    

C. two tickets

D. four tickets

4. Tom meets _______ that day.

A. his parents  

B. some parents  

C. some boys

D. no friends

5. The old man is _______ at the cinema.

A. a driver  

B. a teacher      

C. a ticket-collector    

D. a policeman
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问答题

把桌子放在教室中间，我们从各个方向能看到它原因是：______．
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