2009年计算机网络考研试题
1、（09-33）在OSI参考模型中，自下而上第一个提供端到端服务的层次是
（B）A．数据链路层 B.传输层 C.会话层 D.应用层
解析：自下而上方法的一般从检查物理层开始。自下而上分别称为：物理层、数据链路层、网络层、传输层、会话层、表示层和应用层。传输层是两台计算机经过网络进行数据通信时,第一个端到端的层次，具有缓冲作用。
6、（09-38）主机甲和主机乙间已建立一个TCP连接，主机甲向主机乙发送了两个连续的TCP段，分别包含300字节和500字节的有效载荷，第一个段的序列号为200，主机乙正确接收到两个段后，发送给主机甲的确认序列号是（D）
A．500 B.700 C.800 D.1000
解析：例如，序列号等于前一个报文段的序列号与前一个报文段中数据字节的数量之和。例如，假设源主机发送3个报文段，每个报文段有100字节的数据，且第一个报文段的序列号是1000，那么接收到第一个报文段后，目的主机返回含确认号1100的报头。接收到第二个报文段（其序号为1100）后，目的主机返回确认号1200。接收到第三个报文段后，目的主机返回确认号1300。
7、（09-39）一个TCP连接总是以1KB的最大段发送TCP段，发送方有足够多的数据要发送。当拥塞窗口为16KB时发生了超时，如果接下来的4个RTT（往返时间）时间内的TCP段的传输都是成功的，那么当第4个RTT时间内发送的所有TCP段都得到肯定应答时，拥塞窗口大小是（C）
A．7KB B. 8KB C. 9KB D. 16KB
解析：确定拥塞窗口的大小的过程：在刚建立连接时，将拥塞窗口的大小初始化为该连接所需的最大连接数据段的长度值，并发送一个最大长度的数据段（当然必须是接收窗口允许的）。如果在定时器超时前得到确认，将拥塞窗口的大小增加一个数据段的字节数，并发送两个数据段，如果每个数据段在定时器超时前都得到确认，就再在原基础上增加一倍，即为4个数据段的大小，如此反复，每次都在前一次的基础上加倍。当定时器超时或达到发送窗口设定值，停止拥塞窗口尺寸的增加。这种反复称为慢速启动，所有的TCP协议都支持这种方法。一个TCP连接总是以1KB的最大段发送TCP段，发送方有足够多的数据要发送。当拥塞窗口为16KB时发生了超时，如果接下来的4个RTT（往返时间）时间内的TCP段的传输都是成功的，那么当第4个RTT时间内发送的所有TCP段都得到肯定应答时，拥塞窗口大小是(9KB)。
2010年计算机网络考研试题
7、（10-39）主机甲和主机乙之间已建立一个TCP连接，TCP最大段长度为1000字节，若主机甲的当前拥塞窗口为4000字节，在主机甲向主机乙连接发送2个最大段后，成功收到主机乙发送的第一段的确认段，确认段中通告的接收窗口大小为2000字节，则此时主机甲还可以向主机乙发送的最大字节数是（ A ）
A：1000 B：2000
C：3000 D：4000
2011年计算机网络考研试题
8、（11-40）主机甲与主机乙之间已建立一个TCP 连接，主机甲向主机乙发送了3个连续的TCP 段，分别包含300字节、400字节和500字节的有效载荷，第3个段的序号为900。若主机乙仅正 确接收到第1和第3个段，则主机乙发送给主机甲的确认序号是（B ）
A ．300
B ．500
C ．1200
D ．1400
解答：B 。TCP 段首部中的序号字段是指本报文段所发送的数据的第一个字节的序号。第三个段的序号为900，则第二个段的序号为900-400=500。而确认号是期待收到对方下一个报文段的第一个字节的序号。现在主机乙期待收到第二个段，故甲的确认号是500。
2012年统考计算机考研真题
47.（9 分）主机 H 通过快速以太网连接 Internet ，IP 地址为 192.168.0.8，服务器 S 的 IP 地址为 211.68.71.80。H 与S 使用 TCP 通信时，在 H 上捕获的其中 5 个 IP 分组如 题 47-a 表所示。
题 47-a 表
答下列问题。
（1）题 47-a 表中的 IP 分组中，哪几个是由 H 发送的？哪几个完
成了 TCP 连接建立过程？哪几个在通过快速
以太网传输时进行了填充？
（2）根据题 47-a 表中的 IP 分组，分析 S 已经收到的应用层数据
字节数是多少？
（3）若题 47-a 表中的某个 IP 分组在 S 发出时的前 40 字节如题 47-b 表所
示，则该 IP 分组到达 H 时经过了多少个路由器？
47.【解析】
（1）由于题 47-a 表中 1、3、4 号分组的原 IP 地址均为 192.168.0.8（c0a8 0008H），所以 1，3，4 号分组是由H 发送的。
题47-a 表中 1 号分组封装的TCP 段的FLAG 为02H（即SYN=1，ACK=0）,seq=846b 41c5H，2 号分组封装的TCP 段的 FLAG 为 12H（即 SYN=1，ACK=1），seq=e059 9fefH，ack=846b 41c6H，3 号分组封装的 TCP 段的 FLAG 为 10H（即 ACK=1），seq=846b 41c6H，ack= e059 9ff0H，所以 1、2、3 号分组完成了 TCP 连接建立过程。
由于快速以太网数据帧有效载荷的最小长度为 46 字节，表中 3、5 号分组的总长度为 40（28H）字节，小于 46字节，其余分组总长度均大于 46 字节。所以 3、5 号分组通过快速以太网传输时进行了填充。
（2）由 3 号分组封装的 TCP 段可知，发送应用层数据初始序号为 seq=846b 41c6H，由 5 号分组封装的 TCP 段可知，ack 为 seq=846b 41d6H，所以 5 号分组已经收到的应用层数据的字节数为 846b 41d6H - 846b 41c6H=10H=16。
（3）由于 S 发出的 IP 分组的标识=6811H，所以该分组所对应的是题 47-a 表中的 5 号分组。S 发出的 IP 分组的 TTL=40H=64，5 号分组的 TTL=31H=49，64-49=15，所以，可以推断该 IP 分组到达 H 时经过了 15 个路由器。
____年全国硕士研究生入学统一考试英语试题 Section I Use of English Directions: Read the following text. Choose the best word(s) for each numbered blank and mark A, B, C or D on ANSWER SHEET 1. (10 points). In 1924 America's National Research Council sent two engineers to supervise a series of industrial experiments at a large telephone-parts factory called the Hawthorne Plant near Chicago. It hoped they would learn how stop-floor lighting____1____ workers' productivity. Instead, the studies ended ____2____ giving their name to the Hawthorne effect, the extremely influential idea that the very to being experimented upon changed subjects' behavior. The idea arose because of the ____4____ behavior of the women in the Hawthorne plant. According to ____5____ of the experiments, their hourly output rose when lighting was increased, but also when it was dimmed. It did not ____6____ what was done in the experiment; ____7____something was changed,
2012年全国硕士研究生入学考试英语试题National Entrance Test of English for MA/MS Candidates (NETEM) 跨考英语教研室—杨凤芝 Section Ⅰ Use of English Directions: Read the following text. Choose the best word(s) for each numbered blank and mark [A], [B], [C] or [D]on ANSWER SHEET 1. ( 10 points) The ethical judgments of the Supreme Court justices became an important issue recently. The court cannot_____ its legitimacy as guardian of the rule of law______ justices behave like politicians. Yet, in several instances, justices acted in ways that_____ the court’s reputation for being independent and impartial. Justices Antonin Scalia and Samuel Alito Jr., for example, appeared at political events. That kind of activity makes it less likely that the court’s decisions will be____ as im partial judgments. Part of the problem is that the justices are not _____ by an ethics code. At the very least, the court should make itself_______ to the code of conduct that ______to the rest of the federal judiciary. This and other cases ______the question of whether there is still a _____ between the court and politics. The framers of the Constitution envisioned law____ having authority apart from politics. They gave justices permanent positions ____ they would be free to ____those in power and have no need to_____ political support. Our legal system was designed to set law apart from politics precisely because they are so closely _____. Constitutional law is political because it results from choices rooted in fundamental social ______like liberty and property. When the court deals with social policy decisions, the law it _____is inescapably political — which is why decisions split along ideological lines are so easily _____ as unjust. The justices must _____doubts about the court’s legitimacy by maki ng themselves _____to the code of conduct. That would make their rulings more likely to be seen as separate from politics and, _____, convincing as law. 1 A emphasize B maintain C modify D recognize 2 A when B best C before D unless
2012年全国硕士研究生入学统一考试英语（二）试题 Section 1 Use of Eninglish Directions : Millions of Americans and foreigners see GI.Joe as a mindless war toy ,the symbol of American military adventurism, but that’s not how it used to be .To the men and women who 1 )in World War II and the people they liberated ,the GI.was the 2) man grown into hero ,the pool farm kid torn away from his home ,the guy who 3) all the burdens of battle ,who slept in cold foxholes,who went without the 4) of food and shelter ,who stuck it out and drove back the Nazi reign of murder .this was not a volunteer soldier ,not someone well paid ,5) an average guy ,up 6 )the best trained ,best equipped ,fiercest ,most brutal enemies seen in centuries。 His name is not much.GI. is just a military abbreviation 7) Government Issue ,and it was on all of the article 8) to soldiers .And Joe? A common name for a guy who never 9) it to the top .Joe Blow ,Joe Magrac …a working class name.The United States has 10) had a president or vicepresident or secretary of state Joe。 GI .joe had a career fighting German ,Japanese , and Korean troops . He appers as a character ,or a (12 ) of american personalities, in the 1945 movie The Story of GI. Joe, based on the last days of war correspondent Ernie Pyle. Some of the soldiers Pyleportrayde themselves in the film. Pyle was famous for covering the side of the warl, writing about the dirt-snow –and-mud soldiers, not how many miles wereor what towns were captured or liberated, His reportsthe “willie” cartoons of famed Stars and Stripes artist Bill Maulden. Both menthe dirt and exhaustion of war, the of civilization that the soldiers shared with each other and the civilians: coffee, tobacco, whiskey, shelter, sleep. Egypt, France, and a dozen more countries, G.I. Joe was any American soldier,the most important person in their lives。 1.[A] performed [B]served [C]rebelled [D]betrayed 2.[A] actual [B]common [C]special [D]normal 3.[A]bore [B]cased [C]removed [D]loaded 4.[A]necessities [B]facilitice [C]commodities [D]propertoes 5.[A]and [B]nor [C]but [D]hence 6.[A]for [B]into [C] form [D]against 7.[A]meaning [B]implying [C]symbolizing [D]claiming 8.[A]handed out [B]turn over [C]brought back [D]passed down 9.[A]pushed [B]got [C]made [D]managed 10.[A]ever [B]never [C]either [D]neither 11.[A]disguised [B]disturbed [C]disputed [D]distinguished 12.[A]company [B]collection [C]community [D]colony 13.[A]employed [B]appointed [C]interviewed [D]questioned 14.[A]ethical [B]military [C]political [D]human 15.[A]ruined [B]commuted [C]patrolled [D]gained 16.[A]paralleled [B]counteracted [C]duplicated [D]contradicted 17.[A]neglected [B]avoided [C]emphasized [D]admired 18.[A]stages [B]illusions [C]fragments [D]advancea 19.[A]With [B]To [C]Among [D]Beyond
第1 章计算机网络体系结构 一、单项选择题 1．以下没有采用存储转发技术的交换方式是（）。 A．电路交换 B．报文交换 C．分组交换 D．信元交换 2．分组交换方式是将长的报文分成若干较短的、有固定最大长度的分组。与报文的交换方式不同的是，分组交换方式有（）。 A．报文头B．报文尾C．路由D．分组编号 3．在网络中计算机接收的信号是（）。 A．数字信号 B．模拟信号C．广播信号 D．脉冲信号 4．下面（）拓扑结构可以使用集线器作为连接器。 A．双环状 B．单环状 C．总线状 D．星状 5．根据报文交换的基本原理,可以将其交换系统的功能概括为（）。 A．存储系统 B．转发系统C．存储-转发系统 D．传输控制系统 6．各种网络在物理层互联时要求（）。 A．数据传输率和链路层协议相同 B．数据传输率相同，链路层协议可不同 C．数据传输率可不同，链路层协议相同 D．数据传输率和链路层协议都可不同 7．两个站点之间的距离是10000km，信号在媒体上的传播速率为2×108m／s，线路的带宽是10kbps，现在发送一个3KB 的数据包，那么需要（）时间使得接收方收到数据。 A．0.35S B．0.45S C．0.85S D．1.35S 8．下列交换方式中，（）一次连接沿着一条路由路径发送所有的数据。 A．分组交换 B．报文交换 C．电路交换 D．以上都不是 9．物理层、数据链路层和网络层的PDU 分别是（）。 A．报文、帧、比特 B．报文、分组、比特 C．比特、分组、帧 D．比特、帧、分组 10．为了使数据在网络中的传输延迟最小，首选的交换方式是（）。
11．对计算机网络按照信号频带占用方式来划分，可以划分的网络是（）。A．双绞线网和光纤网 B．局域网和广域网 C．基带网和宽带网D．环形网和总线形网 12．通信子网中的最高层是（）。 A．数据链路层 B．传输层 C．网络层 D．应用层 13．计算机网络中的0SI 参考模型的三个主要概念是（）。 A．服务、接口、协议 B．子网、层次、端口 C．结构、模型、交换 D．广域网、城域网、局域网 14．TCP／IP 模型由以下层次构成：（）。 A．物理层、数据链路层、网络层、传输层、会话层、表示层、应用层 B．网络接口层、互联网层、传输层、应用层 C．物理层、数据链路层、网络层 D．局域网层、广域网层、互联网层 15．在OSI 参考模型中，服务的定义为（）。 A．各层向下层提供的一组原语操作 B．各层间对等实体间通信的功能实现 C．各层通过其SAP 向上层提供的一组功能 D．和协议的含义是一样的 16．在开放系统互连环境中，两个N 层实体进行通信，可能用到的服务是（）。A．N-1 层提供的服务 B．N 层提供的服务 C．N＋1 层提供的服务 D．以上都不对 17．网络协议主要由3 个基本要素组成，即（）。 A．层次、语义和时序 B．语法、原语和时序 C．语法、语义和时序 D．语法、语义和功能 18．以下有关协议和服务说法错误的是（） A.协议是对等实体之间进行逻辑通信而定义的规则或规约的集合。
____年全国硕士研究生入学统一考试英语试题Section I Use of English Directions: Read the following text. Choose the best word(s) for each numbered blank and mark A, B, C or D on ANSWER SHEET 1. (10 points). In 1924 America's National Research Council sent two engineers to supervise a series of industrial experiments at a large telephone-parts factory called the Hawthorne Plant near Chicago. It hoped they would learn how stop-floor lighting____1____ workers' productivity. Instead, the studies ended ____2____ giving their name to the Hawthorne effect, the extremely influential idea that the very to being experimented upon changed subjects' behavior. The idea arose because of the ____4____ behavior of the women in the Hawthorne plant. According to ____5____ of the experiments, their hourly output rose when lighting was increased, but also when it was dimmed. It did not ____6____ what was done in the experiment; ____7____something was changed,
2012年考研英语(二)真题试题及答案 Section 1 Use of Eninglish Directions : Millions of Americans and foreigners see GI.Joe as a mindless war toy ,the symbol of American military adventurism, but that’s not how it used to be .To the men and women who 1 )in World War II and the people they liberated ,the GI.was the 2) man grown into hero ,the pool farm kid torn away from his home ,the guy who 3) all the burdens of battle ,who slept in cold foxholes,who went without the 4) of food and shelter ,who stuck it out and drove back the Nazi reign of murder .this was not a volunteer soldier ,not someone well paid ,5) an average guy ,up 6 )the best trained ,best equipped ,fiercest ,most brutal enemies seen in centuries. His name is not much.GI. is just a military abbreviation 7) Government Issue ,and it was on all of the article 8) to soldiers .And Joe? A common name for a guy who never 9) it to the top .Joe Blow ,Joe Magrac …a working class name.The United States has 10) had a president or vicepresident or secretary of state Joe. GI .joe had a (11)career fighting German ,Japanese , and Korean troops . He appers as a character ,or a (12 ) of american personalities, in the 1945 movie The Story of GI. Joe, based on the last days of war correspondent Ernie Pyle. Some of the soldiers Pyle(13)portrayde themselves in the film. Pyle was famous for covering the (14)side of the warl, writing about the dirt-snow –and-mud soldiers, not how many miles were(15)or what towns were captured or liberated, His reports(16)the “willie” cartoons of famed Stars and Stripes artist Bill Maulden. Both men(17)the dirt and exhaustion of war, the (18)of civilization that the soldiers shared with each other and the civilians: coffee, tobacco, whiskey, shelter, sleep. (19)Egypt, France, and a dozen more countries, G.I. Joe was any American soldier,(20)the most important person in their lives. 1.[A] performed [B]served [C]rebelled [D]betrayed 2.[A] actual [B]common [C]special [D]normal 3.[A]bore [B]cased [C]removed [D]loaded 4.[A]necessities [B]facilitice [C]commodities [D]propertoes 5.[A]and [B]nor [C]but [D]hence 6.[A]for [B]into [C] form [D]against 7.[A]meaning [B]implying [C]symbolizing [D]claiming 8.[A]handed out [B]turn over [C]brought back [D]passed down 9.[A]pushed [B]got [C]made [D]managed 10.[A]ever [B]never [C]either [D]neither 11.[A]disguised [B]disturbed [C]disputed [D]distinguished 12.[A]company [B]collection [C]community [D]colony 13.[A]employed [B]appointed [C]interviewed [D]questioned 14.[A]ethical [B]military [C]political [D]human 15.[A]ruined [B]commuted [C]patrolled [D]gained 16.[A]paralleled [B]counteracted [C]duplicated [D]contradicted
2004年全国硕士研究生入学统一考试英语试题 Section II Use of English Directions: Read the following text. Choose the best word (s) for each numbered blank and mark [A], [B], [C] or [D] on ANSWER SHEET 1. (10 points) Many theories concerning the causes of juvenile delinquency (crimes committed by young people) focus either on the individual or on society as the major contributing influence. Theories 21on the individual suggest that children engage in criminal behavior 22they were not sufficiently penalized for previous misdeeds or that they have learned criminal behavior through 23with others. Theories focusing on the role of society suggest that children commit crimes in 24to their failure to rise above their socioeconomic status, 25as a rejection of middle-class values. Most theories of juvenile delinquency have focused on children from disadvantaged families, 26 the fact that children from wealthy homes also commit crimes. The latter may commit crimes 27 lack of adequate parental control. All theories, however, are tentative and are 28to criticism. Changes in the social structure may indirectly 29juvenile crime rates. For example, changes in the economy that 30to fewer job opportunities for youth and rising unemployment 31make gainful employment increasingly difficult to obtain. The resulting discontent may in 32lead more youths into criminal behavior. Families have also 33changes these years. More families consist of one-parent households or two working parents; 34, children are likely to have less supervision at home 35was common in the traditional family 36. This lack of parental supervision is thought to be an influence on juvenile crime rates. Other 37causes of offensive acts include frustration or failure in school, the increased 38of drugs and alcohol, and the growing 39of child abuse and child neglect. All these conditions tend to increase the probability of a child committing a criminal act, 40 a direct causal relationship has not yet been established. 21.[A] acting[B] relying[C] centering[D] commenting 22.[A] before[B] unless[C] until[D] because 23.[A] interaction[B] assimilation[C] cooperation[D] consultation 24.[A] return[B] reply[C] reference[D] response 25.[A] or[B] but rather[C] but[D] or else 26.[A] considering[B] ignoring[C] highlighting[D] discarding
2012年全国硕士研究生入学统一考试英语试题 Section Ⅰ Use of English Directions: Read the following text. Choose the best word(s) for each numbered blank and mark A, B, C or D on ANSWER SHEET 1. (10 points) The ethical judgments of the Supreme Court justices have become an important issue recently. The court cannot 1 its legitimacy as guardian of the rule of law 2 justices behave like politicians. Yet, in several instances, justices acted in ways that 3 the court’s reputation for being independent and impartial. Justice Antonin Scalia, for example, appeared at political events. That kind of activity makes it less likely that the court’s decisions will be 4 as impartial judgments. Part of the problem is that the justices are not 5 by an ethics code. At the very least, the court should make itself 6 to the code of conduct that 7 to the rest of the federal judiciary. This and other similar cases 8 the question of whether there is still a 9 between the court and politics. The framers of the Constitution envisioned law 10 having authority apart from politics. They gave justices permanent positions 11 they would be free to 12 those in power and have no need to 13 political support. Our legal system was designed to set law apart from politics precisely because they are so closely 14 . Constitutional law is political because it results from choices rooted in fundamental social 15 like liberty and property. When the court deals with social policy decisions, the law it 16 is inescapably political—which is why decisions split along ideological lines are so easily 17 as unjust. The justices must 18 doubts about the court’s legitimacy by making themselves 19 to the code of conduct. That would make ruling more likely to be seen as separate from politics and, 20 , convincing as law. 1. [A] emphasize [B] maintain [C] modify [D] recognize 2. [A] when [B] lest [C] before [D] unless 3. [A] restored [B] weakened [C] established [D] eliminated 4. [A] challenged [B] compromised [C] suspected [D] accepted 5. [A] advanced [B] caught [C] bound [D] founded 6. [A] resistant [B] subject [C] immune [D] prone 7. [A] resorts [B] sticks [C] loads [D] applies 8. [A] evade [B] raise [C] deny [D] settle 9. [A] line [B] barrier [C] similarity [D] conflict 10. [A] by [B] as [C] though [D] towards 11. [A] so [B] since [C] provided [D] though 12. [A] serve [B] satisfy [C] upset [D] replace 13. [A] confirm [B] express [C] cultivate [D] offer 14. [A] guarded [B] followed [C] studied [D] tied 15. [A] concepts [B] theories [C] divisions [D] conceptions 16. [A] excludes [B] questions [C] shapes [D] controls
计算机网络2009年考研试题 一、选择题： 33.在 OSI 参考模型中，自下而上第一个提供端到端服务的层次是 A．数据链路层B.传输层 C.会话层 D.应用层 33.B 分析：在OSI 参考模型中，在传输层提供了端口号，实现了为应用进程之间提供了端到端的逻辑通信，故选【B】。虽然选项中没有网络层，但是还是要提示一下，网络层仅仅是为主机之间提供逻辑通信。 网络要通信，必须建立连接，不管有多远，中间有多少机器，都必须在两头（源和目的）间建立连接，一旦连接建立起来，就说已经是端到端连接了，即端到端是逻辑链路，这条路可能经过了很复杂的物理路线，但两端主机不管，只认为是有两端的连接 34．在无噪声情况下，若某通信链路的带宽为 3kHz，采用 4 个相位，每个相 位具有 4 种振幅的 QAM 调制技术，则该通信链路的最大数据传输速率是 A．12kbps B.24 kbps C.48 kbps D.96 kbps 34.B 分析：假设原始信号中的最大频率为f，那么采样频率f 采样必须大于等于f 的 的 4 4 种振幅， 24=16）的信息，所以该通信链路的最大数据传输速率Cmax =f 采样×log216=24 kbps，故选【B】。 35.数据链路层采用了后退 N 帧（GBN）协议，发送方已经发送了编号为 0~7 的帧。当计时器超时时，若发送方只收到 0、2、3 号帧的确认，则发送方需要重发的帧数是 A．2 B.3 C.4 D.5 35.C （1）就认为前 面（2）后退N 帧重发思想： 3 号确认帧（尽管没有收到1 号确认帧），就可以认为0，1， 2，3 号帧接收方都已经收到，而 4 号帧的确认没有收到，发送方就应该发送4 号帧以及后续所有的帧，即重传4，5，6，7 号帧，即帧数为4，故选【C】。 其实这道题目如果将选项D 改为7，这样就更具有迷惑性，相信会有不少考生认为应该 从1 号帧开始重传，即需要重传1，2，3，4，5，6，7 共计7 帧，这样就会误选D，但是一
2009全国硕士研究生入学考试过关必练_网络试题一．通过选择题过关必练 1.常用的数据传输速率单位有Kbps、Mbps、Gbps与Tbps，1Mbps等于 A. 1×103bps B. 1×106bps C. 1×109bps D. 1×1012bps 2.常用的数据传输速率单位有Kbps、Mbps、Gbps，如果局域网的传输速率为100Mbps， 那么发送1bit数据需要的时间是 A. 1×10-6s B. 1×10-7s C. 1×10-8s D. 1×10-9s 3.网络协议主要由3个要素构成。 A. 语法、语义与体系结构 B. 软件、硬件和数据 C. 语法、语义与时序 D. 体系结构、层次和语法 4.一个功能完善的计算机网络需要制定一套复杂的协议集，对于复杂的计算机网络协 议来说，最好的组织方法是。 A. 连续地址编码模型 B. 层次结构模型 C. 分布式进行通信模型 D. 混合结构模型 5.在网络体系结构中，同层对等实体之间进行信息交换时必须遵守的规则称为。 A. 接口 B. 协议 C. 服务 D. 服务访问点 6.在网络体系结构中，相邻层进行信息交换时必须遵守的规则称为。 A. 接口 B. 协议 C. 服务 D. 服务访问点 7.下列功能中，最好地描述了数据链路层。 A. 保证数据有序、无错和完整地通过网络 B.处理信号通过介质的传输 C. 提供用户与网络的接口 D. 控制报文通过网络的路由选择 8.在网络体系结构中，提供可靠的端到端服务的是。 A. 应用层 B. 运输层 C. 网络层 D. 链路层 9.在TCP/IP体系结构中，UDP协议是一种协议。 A. 应用层 B. 运输层 C. 网络层 D. 网络接口层 10.物理层的4个重要特性是：机械特性、电气特性、功能特性和。 A. 接口特性 B.协议特性 C. 物理特性 D. 规程特性 11.某信道采用8个相伴的调相传输，码元速率为300Baud，则数据传输速率为。 A. 300bps B. 900bps C. 1200bps D. 2400bps 12.信道的最大传输速率受的制约。 A. 信道距离 B.数据编码 C. 信号传输速度 D. 信道带宽 13.用C表示信道的最大信息传输速率，用H表示带宽，用S表示信号功率，用N表 示噪声功率，根据香农公式,C、H、S及N之间的关系是。 A. C=Hlog2(1+S/N) B. C=Hlog2(1+N/S) C. C=Slog2(1+H/N) D. C=Nlog2(1+S/H) 14.让载波信号的频率随调制信号的变化而变化的调制方式叫做。 A. 调相(PM) B. 调幅(AM) C. 调频(FM) D. 脉码调制(PCM) 15.调制解调器（MODEM）的主要功能是。 A. 模拟信号的放大 B. 数字信号的编码 C. 模拟信号与数字信号的转换 D. 数字信号的放大 16.当计算机通过调制解调器（MODEM）发送语音信号时，发送的数据和线路上的信 号之间的关系是。
2012年全国硕士研究生入学统一考试英语(二)试题答案详解Section I Use of English 1.【答案】B 【解析】从空后的句子“他们解放的人们”可以看出，空前的句子表示的应该是参加了第二次大战的男人和女人。只有serve有“服兵役”的意思，所以选B。其他都不符合题意。 2.【答案】B 【解析】空内信息应该是与hero“英雄”意思相对，后面的分句说他背井离乡，经历了很多苦难，显然这里应该是说由普通人平凡人(common man)成长为英雄，所以选B。 3.【答案】A 【解析】本题考查的是词语的搭配关系，承担战争带来的负担，应该用动词bear或shoulder，所以这里选A，bore。 4.【答案】A 【解析】necessities表示“生活必需品”，空外信息food和shelter(食物和住宿)这些就是维持生存最起码的条件。Facilities是设备设施，commodities商品，properties财产，均不符合题意。 5.【答案】C 【解析】not…but，“不是，而是”表转折，不是自愿兵，也没有高的报酬，而是一个普通人。所以选C。 6.【答案】D 【解析】这道题主要考查介词的搭配。根据up______(the best trained, bestequipped, fiercest, most brutal).enemies可以知道是起来反抗敌人，所以选D选项against。 7.【答案】C 【解析】GI。在军事上是Government Issue 的缩略语，所以，GL。这个符号就是象征着这个全称Government Issue。选C。 8.【答案】A 【解析】该句意思为，GI。这个符号出现在给士兵分发的所有物品上，hand out “分发，发放”符合题意。Turn over “移交”，bring back“带回”，pass down“传承，一代一代传下来”在句意上都说不通。 9.【答案】C 【解析】空所在句子的语境为：Joe是个普通名词，一个从未爬到社会顶层的人的名字。Manage表示再怎么经过努力，最终也未获得成功，所以选C。 10.【答案】B 【解析】结合第9题的分析可知，空所在句子实际上是进一步举例说明Joe没有取得大的成就：从来都不曾出现叫做Joe的总统、副总统、国务卿。根据句意只能选never，B。 11.【答案】D 【解析】本题考察词汇辨析。空所在的语境为：GI .Joe有_ _ 的军旅生涯，曾和德国，美国以及韩国的军队作战。由此语境确定选D，其他几项均不符合题意。 12.【答案】B 【解析】本题考察词汇辨析。空所在语境为：他身上体现着美国人的某些特色，或身上结合了美国人的诸多特性。结合语境，可知作者想表达在他身上有很多美国人的典型特色，因而选B。 13.【答案】C 【解析】本题考察词汇辨析。空所在语境为：Pyle _ _ 的士兵也本色出演了该片。结合上句对Ernie Pyle的介绍，可知为一战地记者(warcorrespondent)，确定答案C。