问题 单项选择题

IP地址中,关于C类IP地址的说法正确的是______。

A.可用于中型规模的网络

B.在一个网络中最多只能连接256台设备

C.此类IP地址用于多目的的地址传送

D.此类地址保留为今后使用

答案

参考答案:B

解析:[知识点] IP地址
[评析] A类IP地址用于大型网络,它用7位表示网络,24位表示主机。B类IP地址用于中型网络,它用14位表示网络,16位表示主机。C类IP地址仅用8位表示主机,21位表示网络,在一个网络中最多只能连接256台设备,因此,适用于较小规模的网络。D类IP地址用于多目的地址发送,而E类则保留为今后使用。

阅读理解

阅读理解。

     If you do not use your arms or your legs for some time, they will become weak. When you start using

them again, they slowly become strong again. Everybody knows that.  Yet many people do not seem to

know that memory works in the same way.

     When someone says  that he   has a good memory,    he really means that he   keeps  his memory in

practice by using it. When someone else says that his memory is poor, he really means that he does not

give it enough chance to become strong.

     If a friend says that his arms and legs are weak, we know that it is his own fault(过错). But if he tells

us that he has a poor memory, many of us think that his parents may be blamed(责 备),  and  few of us

know that it is just his own fault. Have you ever found  that  some people can't  read or write but usually

they have better memories ? This is because they cannot read or write and they have to remember things,

they cannot write them  down  in  a small notebook. They  have to  remember days,  names,  songs  and

stories, so their memory is the whole time being exercised.

     So if you want to have a good memory, learn from the people: practise remembering things in a way

as other people do.

1. Someone can't have a good memory if ________.

A. he can't read or write

B. he doesn't use his memory often

C. his parents haven't a good memory

D. he doesn't use his arms or legs for some time

2. If you do not use your arms or legs for some time, ______.

A. you can't use them any more

B. they will become stronger

C. they become weak but they slowly become strong again

D. they become weak and won't become strong until you use them again

3. Which of the following is TRUE ?

A. Your memory  doesn't work in the same way as your arms or legs.

B. Your memory, like your arms or legs, becomes weak if you do not give it enough chance for practice.

C. Don't learn how to read and write if you want to have a better memory.

D. A good memory comes from less practice.

4. Few people know that it is only ______ if a friend has a poor memory.

A. his own fault

B. his parents' fault

C. his teachers' fault

D. his grandmother's fault

5. The writer of this passage wants to tell us ________.

A. how to use our arms or legs

B. how to read and write

C. how to have a good memory

D. how to learn from the people

单项选择题