问题 问答题


在一个基于TCP/IP协议的网络中,每台主机都有会有一个IP地址(如:Internet)。Inter- net上的每台主机都有一个惟一的IP地址,根据获得IP址的方式不同,可以分为静态IP,动态IP。例如:用宽带入网,一定会有一个固定的IP地址,每次连入Internet的IP地址都一样,而用拔号上网(如用:Modem),每次连入Internet时都能从ISP那里获得一个IP地址且每次所获得的可能都不同。ISP为什么能够给用户分配一个IP地址呢这时因为有DHCP服务器的存在,根据在Linux中建立DHCP服务器的实例回答问题。

[问题4]
为了记录IP地址的租用情况,必须创建一个dhcpd.leases文件,初始时这个文件为空,创建文件的过程是怎样的

答案

参考答案:

解析:创建dhcpd.1eases文件的过程如下: 进入/etc/dhcpd目录,执行如下命令: touch dhcpd.leases

阅读理解

The world’s population has reached 7 billion(十亿)according to the United Nations(联合国)by 2011. It comes just 12 years since the total reached 6 billion - with official estimates saying the population will top 8 billion in 2025 and 10 billion before the end of the century.

And it is most likely that the 10-billionth baby will be born in the Asia-Pacific region - where the population growth rate is higher than anywhere else in the world.

Of the 2.3 billion people, the United Nations believes will be added by 2050, more than 1 billion will live in sub-Saharan Africa. The Indian subcontinent(次大陆)will add some 630 million people.

With more people to feed, more houses & medical care to provide, experts say the world’s resources(资源)will face more strain than before.

小题1:According to the picture, the population of the world reached 6 billion in ________.

A. 1987                     B. 1999                     C. 2011

小题2:We know that more than 1 billion will live in  _______ by 2050.

A. sub-Saharan Africa

B. Indian subcontinent

C. the United States

小题3:According to the picture, _______ will have the largest population in 2050.

A. China                        B. India                        C. Nigeria

小题4:The underlined word “strain” in the last paragraph(段落)means “_________”.

A. 破坏                     B. 关闭                     C. 压力

小题5:The population of the world grows ________ according to the picture.

A. slower and slower

B. faster and faster

C. smaller and smaller

单项选择题