问题 单项选择题

如果子网掩码是255.255.192.0,那么主机 (28) 必须通过路由器才能与主机147.69.144.16通信。

A.147.69.127.224

B.147.69.130.33

C.147.69.148.129

D.147.69.191.21

答案

参考答案:A

解析:[要点解析] 子网掩码是一个应用于TCP/IP网络的32位二进制值,它可以屏蔽掉IP地址中的一部分,从而分离出IP地址中的网络部分与主机部分。
[*]
由以上分析可知,在本试题所给出的4个B类网络地址中,主机地址147.69.130.33、147.69.148.129、147.69.191.21和147.69.144.16的子网号相同,它们属于同一子网,可以直接相互通信。而主机 147.69.127.224和147.69.144.16的子网号不同,它们不属于同一子网,即主机147.69.127.224必须通过路由器才能与主机147.69.144.16进行数据通信。
本试题的另一种解题思路是,求得主机地址147.69.144.16的二进制表示形式为“[*]”后,可知其子网号为“10”,子网地址为147.69.128.0/18,该子网可供分配的主机地址范围为147.69.128.1~147.69.191.254。可见,主机地址147.69.130.33、147.69.148.129、147.69.191.21属于该IP地址范围,而主机147.69.127.224没有落入该IP地址范围。

完形填空
I’m Monty Don. Though I’m a host and writer now, I had an unhappy study experience actually. I changed   36  many times.
I first went to school at five. None of my teachers or classmates liked me because I always gave them a lot of trouble. I once put a worm in a girl’s pocket. When I was seven, I was asked to
  37  the school. Then I was sent off to a boarding school. I missed my   38  very much at first; I didn’t want to leave once I returned home. Later I met a very   39  teacher, who cared for me and helped me with my study. He was also the first person to encourage me to act and write. At 13, I moved to Malvern College, but I was kicked out at 15 for   40  school rules. Then I went to another school where I failed my English A level. In fact, I didn’t like studying.
I finally   41  that life shouldn’t be like this. So I retook the exam and got an A grade. And more   42 , I made a decision: to go to college, so I began to   43  for the entrance exam. I finally passed the exam and went to Cambridge to read English. I met my wife there and I was
  44  I made that decision, otherwise I wouldn’t have had a happy family. Looking back on what I’ve   45 , I come to know that if you devote yourself to it, nothing is impossible.
小题1:
A.subjectsB.schoolsC.jobsD.goals
小题2:
A.leave B.joinC.visitD.describe
小题3:
A.friendB.classC.teacherD.family
小题4:
A.rudeB.terrible C.goodD.hard
小题5:
A.breakingB.changingC.keepingD.following
小题6:
A.guessedB.wonderedC.rememberedD.realized
小题7:
A.painfullyB.brieflyC.importantlyD.frequently
小题8:
A.prepare B.callC.waitD.hope
小题9:
A.foolishB.proudC.glad D.afraid
小题10:
A.writtenB.experienced C.dreamedD.concerned
问答题