计算机英语(第二版)chapter13Internet课件.ppt

1、Computer Science in EnglishDesigned and Programmed ByJiang TongqiangMiao TianshunTeaching Assisted CoursewareComputer Science in EnglishII.Grammatical Notes to the Text III.Words Bank to the TextIV.Exercises of the ChapterI.Pre-reading QuestionsChapter 13 InternetII.Grammatical Notes to the Text III

2、.Words Bank to the TextIV.Exercises of the ChapterI.Pre-reading QuestionsChapter 13I.Pre-reading Questions1.What are domain and DNS?2.How many services are provided by the Internet?Name each of them.3.Identify two ways accessing to Internet,and explain the differences between them.1.What are domain

3、and DNS?Reference Key:Domain names tell the computer where to look for the server of the website.Domain names can refer to specific computers,organizations,companies,or other entities.Each domain is named by the way upward from it to the(unnamed)root.The essence of DNS(Domain Name System)is the inve

4、ntion of a hierarchical,domain-based naming scheme and a distributed database system for implementing this naming scheme.It is primarily used for mapping host names and e-mail destinations to IP addresses but can also be used for other purposes.DNS is defined in RFCs 1034 and 1035.Chapter 13I.Pre-re

5、ading Questions2.How many services are provided by the Internet?Name each of them.Reference Key:WWW(World Wide Web),E-mail,FTP(File Transfer Protocol),TelnetChapter 13I.Pre-reading Questions3.Identify two ways accessing to Internet,and explain the differences between them.Reference Key:Refers to con

6、necting a device to a network via a modem and a public telephone network,dial-up access is really just like a phone connection,except that the parties at the two ends are computer devices rather than people.Because dial-up access uses normal telephone lines,the quality of the connection is not alway

7、s good and data rates are limited.In the past,the maximum data rate with dial-up access was only 56 Kbps(56000 bits per second).Chapter 13I.Pre-reading Questions3.Identify two ways accessing to Internet,and explain the differences between them.Digital Subscriber Line,or DSL,is a method of accessing

8、the internet via telephone lines.It differs from dial-up access in that it makes use of a special frequency spectrum which allows both digital information and telephone services to run through the same cable.It is also a good deal faster than dial-up Internet,theoretically processing upwards of 10 m

9、egabits per second,in contrast to dial-ups sluggish 56 kilobits(or roughly five percent of a megabit).In fact such extremely fast speeds are rarely obtained by DSL services because most phone companies install artificial“speed caps”to impose a universal level of service on their lines.However,even a

10、 slower-paced DSL connection can make for easy and responsive web navigation.本句是一个并列句。连词and连接两个句子：A network is a collection of computers和the Internet is a network of networks。句中的that引导定语从句修饰computers，连接副词so引导状语从句，表示that are connected together的目的。1.A network is a collection of computers that are conn

11、ected together so they can share information,and the Internet is a network of networks.II.Grammatical Notes to the Text句首的不定式to make it easier做目的状语，其中的it是形式宾语，其内容由不定式for sb to remember表达出来。主句的谓语有短语be expressedas(被表述为)。句末的above是形容词，作后置定语，修饰介词短语like the one中的代词one。2.To make it easier for us humans to

12、remember,IP addresses are normally expressed in decimal format as a“dotted decimal number”like the one above.II.Grammatical Notes to the Text该句第一个which引导的非限制性定语从句修饰a local DNS server。第二个which引导的非限制性定语从句则修饰the resolver。3.The resolver sends a UDP packer to a local DNS server,which then looks up the na

13、me and returns the IP address to the resolver,which then returns it to the caller.II.Grammatical Notes to the Textafter establishing the TCP connection to port 25为该句的时间状语，相当于一个由after引导的时间状语从句。现在分词短语operating as the client修饰the sending machine,operating as the server则修饰the receiving machine。4.After e

14、stablishing the TCP connection to port 25,the sending machine,operating as the client,waits for the receiving machine,operating as the server,to talk first.II.Grammatical Notes to the Text限制性定语从句that supports the Internet修饰该句主语the software。限制性定语从句upon which everything else修饰technical services。5.The

15、software that supports the Internet provides a large number of technical services upon which everything else is built.II.Grammatical Notes to the Text现在分词结构作状语，表结果。限制性定语从句do need to talk about修饰four important Internet services，其中在实义动词need前加上助动词do表示强调，强调动作talk about。6.Nevertheless,there are four impo

16、rtant Internet services we do need to talk about.II.Grammatical Notes to the Text本句中的which引导非限定性定语从句，修饰mailbox。连接副词until引导的状语从句表示时间。7.There,it will be stored in the recipients“mailbox,”which is determined by his or her user name,until he or she picks it up.II.Grammatical Notes to the Text本句的主体结构如下：t

17、he problem is that。句中第一个that 是代词，做表语，其后的they amplify the entire signal是表语的同位语，表示that的内容。第二个that引导的定语从句they receive，修饰signal。8.The problem with repeaters is that they amplify the entire signal that they receive,including any line noise.II.Grammatical Notes to the Text本句是一个强调句型：It is that。介词短语by learn

18、ing which MAC addresses are live on the network是该句的强调成分，充当句中的状语。which引导的从句作动词learn的宾语(从句)。该句的主体结构可变换成：the bridge is able to control traffic and keep it from spreading。其中is able to 和keep作为该句的并列谓语。句中的第二个和第三个that分别引导定语从句修饰traffic 和segment。9.It is by learning which MAC addresses are live on the network

19、that the bridge is able to control traffic that is local to a particular segment and keep it from spreading to other network segments that are being serviced by another bridge switch.II.Grammatical Notes to the Text该句是个复合句，主句是it differs。连接副词in that 引导出状语从句it makes use of a special frequency spectrum

20、。连词which 引导定语从句修饰spectrum。in that 意思是“由于，因为”。10.It differs from dial-up access in that it makes use of a special frequency spectrum which allows both digital information and telephone services to run through the same cable.II.Grammatical Notes to the Textadminister Ed5ministE v.管理，执行管理，执行influential

21、 7influ5enFEl adj.有影响的，有势力的有影响的，有势力的unique ju:5ni:k adj.唯一的，独特的唯一的，独特的respectively ri5spektivli adv.分别地，各个地分别地，各个地octet Ck5tet n.八位位组八位位组,八位字节八位字节(=byte)troubleshooting 5trQbl 5Fu:tiN n.问题解答问题解答identifier ai 5dentifaiE n.标识符标识符uniform 5ju:nifC:m adj.统一的，一致的统一的，一致的insensitive in5sensitiv adj.感觉迟钝的感觉迟

22、钝的undeliverable 5Qndi5livErEbl adj.无法送达的无法送达的trigger 5triE vt.引起，触发引起，触发beneficial beni5fiFEl adj.有益的，受益的有益的，受益的axon 5AksCn n.轴突轴突 nutshell 5nQtFel n.坚果壳坚果壳regenerate ri5dVenErit vt.使新生，重建使新生，重建integrity in5teriti n.完整，完整性完整，完整性amplify 5Amplifai vt.放大，增强放大，增强discernable dis:nEbl adj.可辨别的，可认识的可辨别的，可认

23、识的twist twist v.扭曲，缠绕扭曲，缠绕outgrow aut5rEu vt.过大而不适于过大而不适于conserve kEn5sE:v vt.保存，保藏保存，保藏overwhelming 7EuvE5welmiN adj.压倒性的压倒性的dedicated 5dedikeitid adj.专用的专用的filtration fil5treiFEn n.过滤，筛选过滤，筛选IV.ExercisesComprehensionI.Filling BlanksVocabularyII.True or FalseIII.Matching TermsSummaryVII.Cloze(Summa

24、rizing the Text)VIII.Translating SentencesCollocationIV.Answering QuestionsV.Selecting WordsVI.Conceptual PhrasesTranslation I.Fill in the following blanks.I.Fill in the following blanks.II.True or False.III.Matching the terms.IV.Answer the following questions.IV.Answer the following questions.IV.An

25、swer the following questions.IV.Answer the following questions.V.Fill in the blanks with the words given below.Change the form where necessary.integrity respectively conserve amplify boost uniform comprehend infinite influential V.Fill in the blanks with the words given below.Change the form where n

26、ecessary.integrity respectively conserve amplify boost uniform comprehend infinite influential V.Fill in the blanks with the words given below.Change the form where necessary.integrity respectively conserve amplify boost uniform comprehend infinite influential V.Fill in the blanks with the words giv

27、en below.Change the form where necessary.integrity respectively conserve amplify boost uniform comprehend infinite influential V.Fill in the blanks with the words given below.Change the form where necessary.integrity respectively conserve amplify boost uniform comprehend infinite influential V.Fill

28、in the blanks with the words given below.Change the form where necessary.integrity respectively conserve amplify boost uniform comprehend infinite influential V.Fill in the blanks with the words given below.Change the form where necessary.integrity respectively conserve amplify boost uniform compreh

29、end infinite influential V.Fill in the blanks with the words given below.Change the form where necessary.integrity respectively conserve amplify boost uniform comprehend infinite influential V.Look at the following sentence taken from your reading passage.Just think about what else you can“identify”

30、and fill in the sentences with the right words.e.g.IP addresses with a first octet from 1 to 126 are part of this class.The other three octets are used to identify each host.2.Having identified the pr_,the question arises of how to overcome it.oblem 1.Scientists claim to have identified ch_ produced

31、 by certain plants which have powerful cancer-combating properties.emicals4.The young man tried to identify her pe_.rfume 3.Can you identify your um_ among this lot?brella6.The local police authorities have already identified around 10 murder su_.spects 5.He was confident enough to identify be_ with

32、 goodness.autyVII.Choose the best one of the four answers given to fill in each blank.Internet is a worldwide and opening interconnected computer network.It is a special network,1 which users can administer themselves.Internet is based on TCP/IP 2 .It can provide various information resources and ma

33、ny network services for network 3 .Intranet is the generic 4 for a collection of private computer networks within an organization.An intranet uses network technologies as a tool to facilitate communication 5 people or workgroups to improve the data 6 capability and overall knowledge base of an organ

34、izations employees.An Extranet is actually an Intranet that is partially 7 to authorized outsiders.Intranet network is connected to the 8 ,if it allows access 9 the Internet,will be an Extranet.The actual server will reside behind a firewall.The firewall helps to control access between the Intranet

35、and Internet 10 access to the Intranet only to people who are suitably authorized.1.A.on B.in C.for D.with2.A.agreement B.serial C.task D.protocol3.A.customers B.consumers C.computers D.users4.A.word B.concept C.term D.name5.A.among B.between C.in D.at6.A.share B.sharing C.shared D.to share 7.A.acce

36、ssible B.access C.accessibly D.assess 8.A.intranet B.extranet C.internet D.wannet 9.A.from B.into C.to D.by10.A.to permit B.permit C.permitted D.permitting1.A2.D3.D4.C5.B6.B7.A8.C9.A10.D1.The ARPAnet was designed so that even if part of its physical structure were destroyed,information could still b

37、e sent to any remaining destination.VIII.Translate the following into English.2.To map a name onto an IP address,an application program calls a library procedure called the resolver,passing it the name as a parameter.VIII.Translate the following into English.3.Within the Internet,e-mail is delivered

38、 by having the source machine establish a TCP connection to port 25 of the destination machine.VIII.Translate the following into English.4.An intranet uses network technologies as a tool to facilitate communication between people or workgroups to improve the data sharing capability and overall knowledge base of an organizations employees.VIII.Translate the following into English.5.An organizations intranet typically includes Internet access but is firewalled so that its computers cannot be reached directly from the outside.EndVIII.Translate the following into English.