问题 填空题

IP数据包在传输过程中如遇到一些差错与故障,一般会向源主机发送 【11】 报文。

答案

参考答案:ICMP

解析:[知识点] 网络体系结构与协议的基本概念
[评析] 为了应对IP数据报在传输过程中出现的各种差错与故障,TCP/IP中专门设计了网络控制报文协议 ICMP(Internet Control Message Protocol),作为传输差错报文与网络控制信息的主要手段。当中间网关发现传输错误时,立即向源主机发送ICMP报文报告出错情况,源主机接收到该报文后由ICMP软件确定错误类型或确定是否重发数据包。

阅读理解

阅读理解。

Dear Sir,

    I have to travel every day from Souk Road to the airport. Two buses travel along their route (路线): the

number 49 and number 16. But by the time the number 16 bus reaches Souk Road it is always full, so I can't

get on it. I have to wait for the number 49, because sometimes there are empty seats on it.

    The timetable says that there are buses from Souk Road to the airport every ten minutes. If this is so, why

do I have to wait half an hour for a bus nearly every day?

    The regulations say that if there are empty seats on a bus, the bus must stop at every stop where people are

waiting. Why do the half-empty buses go straight past me when I am standing at the bus stop?

    The regulations say that no bus may carry more than 40 seated passengers and 20 standing passengers.

Yesterday I was the first to get off the bus when it reached the airport. I counted the other passengers as they

got off. There were 129 of them.

    It is clear that our bus companies break the regulations and think little of their passengers. Can nothing be

done to make your service better? 

                                                                                                                                     Yours

                                                                                                                                    Tired passenger

1. The writer has to take Bus No.49 because _____. [ ]

A. it arrives on time

B. it is not always full

C. it travels faster

D. it has fewer seats on it

2. How long does the writer usually have to wait for a bus? [ ]

A. Ten minutes.

B. One hour.

C. Half an hour.

D. Nearly a day.

3. The regulations say that each bus may carry _____ passengers at most. [ ]

A. 20

B. 40

C. 60

D. 129

4. From the passage we can see that _____. [ ]

A. the bus service was poor

B. no buses except the No.49 bus passed Souk Road

C. no passengers took their buses

D. the writer was always the first to get on the bus

单项选择题 A2型题