计算机英语（中篇共上中下3篇）

1ProgrammingLanguages2Object-orientedProgramming3VisualProgramming4WebProgrammingLeadin

Acomputerprogramisasequenceofinstructionstoperformaspecifiedtaskbythecomputer.Computerprogrammingistheactofwritingtheseprogramsandthelanguageusediscalledtheprogramminglanguage.Moreprecisely,computerprogramming,oftenshortenedtoprogrammingorcoding,istheprocessofwriting,testing,andmaintainingthesourcecodeofcomputerprograms.Withinsoftwareengineering,programmingisregardedasonephaseinasoftwaredevelopmentprocess,aswehavediscussedinChapter3.Aswehumanbeingshavedevelopedsomanylanguagestocommunicateamongourselves,computerscientistshavedevelopedseveralcomputer-programminglanguagestoprovideinstructionsforthecomputer.Someonewhocanwritecomputerprogramsorinotherwords,someonewhocandocomputerprogrammingiscalledacomputerprogrammer.1ProgrammingLanguagesProgrammingLanguages1

Programminglanguagesaretheartificiallanguagesusedtowriteasequenceofinstructionsthatcanberunbyacomputer.Similartonaturallanguages,programminglanguageshaveavocabulary,grammar,andsyntax.Thereareseveralhundredprogramminglanguages.Someweredevelopedforspecificcomputers;othersweredevelopedforspecificuses,suchasscientificorbusinessapplications.ProgrammingLanguages1

Programminglanguagesareclassifiedintofivemajorcategories:machinelanguages,assemblylanguages,third-generationlanguages,fourth-generationlanguagesandnaturallanguages.Theyareeitherlow-levelorhigh-levellanguages.Machineandassemblylanguagesarereferredtoaslow-levellanguages;third-generation,fourth-generationandnaturallanguagesarecalledhigh-levellanguages.Figure5-1helpsillustratesuchaclassification.ProgrammingLanguages1

Alowlevellanguageiswrittentorunononeparticularcomputerwhileahighlevellanguageishighlyportable,meaningthatitcanrunonmanydifferenttypesofcomputers.Programswritteninahigh-levellanguagemaytakelongertoexecuteanduseupmorememorybecauseitmustbetranslatedintoamachinelanguagebeforeacomputercanunderstandit.Thetranslationisperformedusingoneoftwotypesofprograms:acompileroraninterpreter.Acompilerconvertstheentiresourceprogramintomachinelanguage(binarydigits)atonetime.Whilecompiling,thecompilerchecksthesourceprogram’ssyntaxandverifieswhethertheprogramproperlydefinesthedata.Thenthecompilerproducesaprogramlisting,whichcontainsalistofanysyntaxerrors.Thislistinghelpstheprogrammermakenecessarychangestothesourcecodeanddebugtheprogram.ProgrammingLanguages1

Whileacompilertranslatesanentireprogramatonce,aninterpretertranslatesoneprogramcodestatementatatime.Thatis,aninterpreterreadsacodestatement,andthenexecutestheinstructionswithoutanyfurtherconversion.Thisisthecompleteprocessofinterpretingonestatementanditwillnotmovetothenextcodestatementuntilitfinishesthisprocess.ProgrammingLanguages1

Amachinelanguage,alsocalledthefirst-generationlanguage,isasetofinstructionsexecuteddirectlybyacomputer'sCPU.Itisthelowestlevelofprogramminglanguages.Inmachinelanguages,instructionsarewrittenassequencesofbinarydigits(1sand0s)thatacomputercanunderstanddirectly.Machinelanguageprogramsrunonlyonthecomputerforwhichtheyweredeveloped;thatis,theyaremachine-dependt.01MachineLanguages

Whileitispossibletowriteprogramsdirectlyinmachinelanguages,itistediousanderrorpronetomanageindividualbitsandcalculatenumericaladdressesandconstantsmanually.[1]Thus,programmersdonotwriteprogramsinmachinelanguages.Instead,theywriteprogramsinhigh-levellanguagesorassemblylanguageswhichareconvertedtomachinelanguagesandthenexecutedbythecomputer.ProgrammingLanguages1

Becausemachinelanguageprogramsweresodifficulttowrite,asecondgenerationofprogramminglanguages,calledassemblylanguages,evolved.Withanassemblylanguage,instructionsarewritteninmeaningfulabbreviations.Forinstance,programmerscanwritecodessuchasAforaddition,Cforcompare,Lforload,andMformultiply.Itismoreconvenientthanthewayofbitsinmachinelanguages.02AssemblyLanguages

Assemblylanguagessharecertainfeatureswithmachinelanguages.Forexample,itispossibletomanipulatespecificbitsinbothassemblyandmachinelanguages.Programmersuseassemblylanguageswhenitisimportanttominimizethetimeittakestorunaprogram,becausethetranslationfromassemblylanguagestomachinelanguagesisrelativelysimple.ProgrammingLanguages1

Generally,assemblylanguagesareintermediatelanguagesthatareveryclosetomachinelanguagesanddonothavetheleveloflinguisticsophisticationexhibitedbyotherhigh-levellanguages,butmuststillbetranslatedintomachinelanguages.[2]Assemblylanguagesareusedtoenhancethespeedofexecution,especiallyinearlyPCwithlimitedprocessingpowerandRAM.Currently,althoughitisnotaspopularashigh-levellanguagesinprogramming,itplaysanirreplaceableroleinsomefields.Forinstance,thoughmostofthepartsoftheLinuxkernelarewritteninClanguage,somekeypartshavetobewritteninassemblylanguagestomaximizetheperformanceofhardware.02AssemblyLanguagesProgrammingLanguages1

Unlikelow-levellanguages,high-levellanguagesmakeiteasyforprogrammerstodevelopandmaintainprograms.Inaddition,theyaremachine-independent,whichmeanstheycanrunonmanydifferenttypesofcomputers.

Athird-generationlanguageisoneofthehigh-levellanguages;alsothemostcommonlyusedone.ItsinstructioniswrittenasaseriesofEnglish-likewords.Forexample,aprogrammerwritesADDforadditionorPRINTtoprint.Manythird-generationlanguagesalsousearithmeticoperatorssuchas*formultiplicationand+foraddition.TheseEnglish-likewordsandarithmeticnotationssimplifytheprogramdevelopmentprocess.03Third-generationLanguagesProgrammingLanguages1

Third-generationlanguagesarealsoknownasprocedurallanguages.Theyrequirethattheprograminstructionstellthecomputerwhattoaccomplishandhowtodoit.[3]Theyallowprogramstobeshorterandeasierforthecomputertoread,buttheyrequiretheprogrammertodesigneachproceduretobegeneralenoughtobeusedindifferentsituations.LanguagessuchasC,BASICandFORTRANarecommonprocedurallanguages.03Third-generationLanguagesProgrammingLanguages1

Particularly,theCprogramminglanguage(SeeFigure5-2)hasbeenaroundforseveraldecadesandhaswonwidespreadacceptancebecauseitgivesprogrammersmaximumcontrolandefficiency.Itisalsoeasytolearn.Coriginallywasdesignedasalanguagetowritesystemsoftware.Today,itisusedtodevelopawidevarietyofsoftware,includingoperatingsystemsandapplicationsoftwaresuchaswordprocessingandspreadsheetprograms.Itrunsonpracticallyanytypeofcomputerwithanyoperatingsystem,butmostoftenisusedwiththeUNIXoperatingsystem.03Third-generationLanguagesProgrammingLanguages1

Similartoathird-generationlanguage,afourth-generationlanguageemploysEnglish-likestatements.However,theirmajordistinctionliesinthatfourth-generationlanguagesarenonprocedural,whichmeanstheprogrammeronlyspecifieswhattheprogramshouldaccomplishwithoutexplaininghow.Inthisway,itcansaveprogrammersalotoftimeandeffortbecausetheydonotneedtowriteasmanylinesofcodeastheydowithprocedurallanguagesandevenuserscanwriteprogramsbecauseitrequiresverylittleprogrammingbackground.Fourth-generationlanguagesconsistofreportgenerators,querylanguages,applicationgenerators,andinteractivedatabasemanagementsystemprograms.Someofthemaretoolsforend-usersandsomearetoolsforprogrammers.04Fourth-generationLanguagesProgrammingLanguages1

Manyfourth-generationlanguagesworkwithadatabase.Theyallowdatabaseadministratortodefinethedatabaseanditsstructure,helpprogrammersmaintainthedatainthedatabase,andallowuserstoquerythedatabase.ASQL(StructuredQueryLanguage)isapopularfourth-generationlanguageusedwithrelationaldatabasemanagementsystems.Currentlythoughthefourth-generationlanguagedoesimprovetheproductivityofprogramming,itmaynotentirelyreplacethethird-generationlanguagebecauseitisusuallyfocusedonspecifictasksandhenceoffersfeweroptions.[4]Intermsofapplication,itcanbebusinessorientedoritcandealwithsometechnicaldomain.04Fourth-generationLanguagesProgrammingLanguages1

Whenitcomestonaturallanguages,peoplemaycomeupwithordinaryhumanlanguages,suchasEnglish,Spanishandsoon.Butamongprogramminglanguages,naturallanguages,sometimescalledfifth-generationlanguages,arequerylanguagesthatallowuserstoenterrequeststhatresemblehumanspeech.Thatis,naturallanguagesusehumanlanguagetogivepeopleamorenaturalconnectionwithcomputers.05NaturalLanguagesProgrammingLanguages1

Somefourth-generationlanguagesmightseemprettyclosetohumancommunication,butnaturallanguagesareevencloser.Withfourth-generationlanguages,someratherroutineinquiriesareusedwhereasnaturallanguagesallowquestionsorcommandstobeframedinamoreconversationalway.Naturallanguagesarepartofthefieldofstudyknownasartificialintelligence.Currentlytheyarepopularinthemedicalfield,butarenotwidelyusedinbusinessapplications.05NaturalLanguages2Object-orientedProgramming

Object-orientedprogramming(OOP)isaprogrammingmethodthatcombinesdataandinstructionsforprocessingthatdataintoaself-sufficient“object”thatcanbeusedinotherprograms.Object-orientedProgramming2

InOOP,anobjectisanitemthatcancontainbothdataandtheproceduresthatreadormanipulatethedata.Astudentobject,forexample,mightcontaindataaboutastudent(studentID,firstname,lastname,addressandsoon)andinstructionsonhowtoprintthestudentrecordortheformularequiredtocalculateastudent'stuitionrates.Theproceduresintheobjectarecalledmethods,oroperations,whichcontainactivitiesthatreadormanipulatethedata.Thedataelementsarecalledattributes,orvariables.5.2.1BasicConceptsObject-orientedProgramming2

Theconceptofpackagingmethodsandattributesintoasingleobjectiscalledencapsulation;thatis,thedetailsoftheobjectareencapsulated,orhidden,fromtheuser.Theuserknowsthemethodsthatcanberequestedoftheobjectbutdoesnotknowthespecificsofhowthemethodisperformed.Forexample,whileyouknowhowtoaccelerateyourcar,youmightnotknowthemechanicsofhowthecaractuallyspeedsupwhenyoupushthegaspedal.Thus,thedetailsofyourcarareencapsulated,orhidden,fromyou.5.2.1BasicConceptsObject-orientedProgramming2

Anobjectmaybepartofalargercategoryofobjects,calledaclass.Everyobjectinaclasssharessimilarmethodsandattributesastheoriginalobject.Eachclasscanhavesubclassesthatcaninheritallorsomeofthecharacteristicsoftheclass.Theconceptoflowerlevelsinheritingmethodsandattributesofhigherlevelsiscalledinheritance.Inrelationtoeachsubclass,theclassbecomesthesuperclass.Subclassescanalsodefinetheirownmethodsandattributesthatarenotpartoftheirsuperclass.Thestructureofaclassanditssubclassesiscalledtheclasshierarchy.5.2.1BasicConceptsObject-orientedProgramming2

Amajorbenefitoftheobject-orientedapproachistheabilitytoreuseandmodifyexistingobjects.Asnotedabove,methodsandattributescanbeinherited.Thus,programmerscangetreusablecodeswhichcanresultinnotonlytime-savingworkbutalsomorereliableandefficientprograms.5.2.1BasicConceptsObject-orientedProgramming2

Iftheobject-orientedapproachtoprogramdevelopmentisused,thentheprogramminglanguageusedtoimplementthedesignmodelisanobject-orientedprogramminglanguage.OnefeatureofanOOPlanguageisthatitisevent-driven.EventissimplytheOOPtermformessage.Anevent-drivenprogramchecksforandrespondstoasetofmessagesorevents.Aneventcouldbepressingakeyonthekeyboard,clickingthemouse,ortypingavalueintoatextbox.5.2.2OOPLanguageObject-orientedProgramming2

ThefirstOOPlanguagewascalledSimula67[5].C++(SeeFigure5-3)andJava(SeeFigure5-4)arethemostpopularOOPlanguagestoday.C++isageneral-purposeprogramminglanguagewidelyusedinthesoftwareindustry.Itspurposeistopreciselydefineaseriesofoperationsthatacomputercanperformtoaccomplishatask.C++powersmajorsoftwarelikeFirefox,WinampandAdobeprograms.It’susedtodevelopsystemssoftware,applicationsoftware,high-performanceserverandclientapplicationsandvideogames.5.2.2OOPLanguageObject-orientedProgramming2

TheJavaprogramminglanguageisdesignedespeciallyforuseindistributedapplicationsoncorporatenetworksandtheInternet.ItbuildsonthefamiliarandusefulfeaturesofC++whileremovingitscomplex,dangerous,andsuperfluouselements.Thus,itissafer,simpler,andeasiertouse.5.2.2OOPLanguageObject-orientedProgramming23VisualProgramming

Visualprogrammingisamethodofcreatingprogramsbyusingiconsthatpresentcommonprogrammingroutines.Theprogrammermakesconnectionsbetweenobjectsbydrawing,pointing,andclickingondiagramsandiconsandbyinteractingwithflowcharts.ItsgoalistomakeprogrammingeasierforprogrammersandmoreaccessibletononprogrammersbyborrowingOOPconceptsbutexercisingtheminagraphicalorvisualway.VisualProgramming3

VisualBasic(SeeFigure5-5)isanobject-orientedprogramminglanguagethatwasdevelopedbyMicrosoftasatoolbywhichusersofMicrosoft'sWindowsoperatingsystemcoulddeveloptheirownGUIapplications.ThefirststepinbuildingaVisualBasicapplicationistodesigntheGUIusingVisualBasicobjects.VisualBasicobjects,orcontrols,includeitemssuchascommandbuttons,textboxes,andlabels.Next,writeanycodeneededtodefineprogramevents.AneventinVisualBasiccanbetheresultofanactioninitiatedbyauser.Oncethesestepsarecompleted,thefinalapplicationcanbegenerated.DifferentFormsofSoftware3

ItissometimescalledaRapidApplicationDevelopment(RAD)systembecauseitenablesprogrammertoquicklybuildprototypeapplications.EvennoviceprogrammerscancreateprofessionalWindows-basedapplicationsusingVisualBasic.WithitsconvenienceandthepopularityoftheWindowsoperatingsystem,VisualBasichasbecomeoneofthemostwidelyusedprogramminglanguages.DifferentFormsofSoftware34WebProgrammingWebProgramming4

AcollectionoflinkeddocumentsaccessibleontheInternetisknownastheWorldWideWeb,orsimplytheWeb.EachdocumentontheWeb,calledaWebpage,isalinkeddocumentthatcancontaintexts,graphics,videos,andsound.Somemarkuplanguages[6]andprogramminglanguagesareusedtobuildanddevelopsuchmultimediasitesontheWeb,includingHTML,Java,JavaScript,XML,etc.WebProgramming4

HTML(HypertextMarkupLanguage)isanauthoringlanguageforcreatingWebdocuments.Althoughnotactuallyaprogramminglanguage,HTMLisalanguagethathasspecificsyntaxrulesfordefiningtheplacementandformatoftexts,graphics,videos,andsoundonaWebpage.ItdefinesthestructureandlayoutofaWebpagebyusingavarietyoftagsandattributes.ThecorrectstructureforanHTMLdocumentstartswith<HTML><HEAD>(enterherewhatdocumentsisabout)<BODY>andendswith</BODY></HTML>.AlltheinformationtobeincludedinaWebpagefitsinbetweenthe<BODY>and</BODY>tags.Moreexamplesoftagsare<B>toboldtext,<P>toindicateanewparagraph,and<FTR>todisplayahorizontalruleacrossthepage.01HTMLWebProgramming4

OneofthemainfeaturesofHTMLisitsabilitytoinserthyperlinksintoadocument.HyperlinksenableuserstodisplayanotherWebdocumentsimplybyclickingonalinkarea(usuallyunderlinedorhighlighted)onthecurrentscreen.Alinkmayeitherbeaword/wordsoranimage.HTMLcodecanbewrittenusinganytexteditororstandardwordprocessingsoftwarepackage.Forexample,MicrosoftWordcansavedocumentsinHTMLformat.HTMLwrittenbythesetoolscancreatebasicWebpagesthatcontaintextsandgraphics.Inaddition,therearevariousHTMLeditorsforcreatingWebpagesbychoosingmenuoptionsandfillingouttemplates,suchasAdobePageMillandMicrosoftFrontPage,whicharecapableofcreatingmoresophisticatedWebpagesthatincludevideos,sound,animation,andotherspecialeffects.01HTMLWebProgramming4

JavaisaWebprogramminglanguagedevelopedbySunMicrosystems.ItisamajordeparturefromtheHTMLcodingthatmakesupmostWebpages.Asnotedearlier,itisanobject-orientedlanguagesimilartoC++butsimplifiedtoeliminatelanguagefeaturesthatcausecommonprogrammingerrors.Javasourcecodefiles(fileswitha.javaextension)arecompiledintoaformatcalledbytecode(fileswitha.classextension),whichcanthenbeexecutedbyaJavainterpreter.CompiledJavacodecanrunonmostcomputersbecauseJavainterpretersandruntimeenvironments,knownasJavaVirtualMachines(VMs),existformostoperatingsystems,includingUNIX,MacOSandWindows.02JavaWebProgramming4

WithJava,bigapplicationprogramscanbebrokenintomini-applications,or“applets”,thatcanbedownloadedofftheInternetandrunonanycomputer.Moreover,JavaenableaWebpagetodeliverappletsthatwhendownloadedcanmakeWebpagesinteractive.Withitssimplicity,robustnessandportability,asof2016,Javaisoneofthemostpopularprogramminglanguagesinuse,particularlyforclient-serverWebapplications.02JavaWebProgramming4

JavaScriptisaninterpretedscriptinglanguage[7]thatallowsWebauthorstoaddfunctionalitytotheirWebpagesbyinsertingJavaScriptcodewithinanHTMLdocument.WhereasHTMLindicatesthelayoutandcontentsofaWebpage,JavaScriptcanbringtheWebpagetolifebyaddingdynamiccontentsandinteractiveelementssuchasscrollingmessagesanddatainputforms.03JavaScriptWebProgramming4

JavaScriptisoneofthecoretechnologiesofWorldWideWebcontentproduction;themajorityofWebsitesemployitanditissupportedbyallmodernWebbrowserswithoutplug-ins.ItisalsousedinenvironmentsthatarenotWeb-based,suchasPDFdocuments,site-specificbrowsers,anddesktopwidgets.AlthoughitsharesmanyofthefeaturesofthefullJavalanguage,JavaScriptisasimplerlanguage.NowadaysJavaScriptisendorsedbyanumberofsoftwarecompaniesandisanopenlanguagethatanyonecanusewithoutpurchasingalicense.03JavaScriptWebProgramming4

XML(ExtensibleMarkupLanguage)isamarkuplanguagethatdefinesasetofrulesforencodingdocumentsinaformatthatisbothhuman-readableandmachine-readable.BeingdevelopedbytheWorldWideWebConsortium(W3C),XMLismoreversatilethanHTML.ItmakesiteasyformachinetoreadWebsitesbyenablingWebdeveloperstoadddescriptivetagstoaWebpage.Inthisway,forexample,specificsitescanbepinpointedwhenwesearchthem.Furthermore,withXML,alinkcanbepointedtomultipleWebsitesinsteadofasinglesite.04XMLWebProgramming4

TherearehundredsofdocumentformatsusingXML.XML-basedformatshavebecomethedefaultofmanyoffice-productivitytools,includingMicrosoftOffice,OpenO,LibreOfficeandApple’siWork.ItalsohascomeintocommonusefortheinterchangeofdataovertheInternet.04XMLWordsWordsprogrammer['prəugræmə]n.程序设计员syntax['sintæks]n.语法verify['verifai]v.验证constant['kɔnstənt]n.常量linguistic[liŋ'gwistik]adj.语言的accomplish[ə'kʌmpliʃ;ə'kɔm-]v.完成distinction[dis'tiŋkʃən]n.区别database['deitəbeis]n.数据库oriented['ɔːrientid;'əu-]adj.以……为方向的domain[dəu'mein]n.领域resemble[ri'zembl]v.类似routine[ruː'tiːn]adj.常规的conversational[ˌkɔnvə'seiʃənəl]adj.对话的object-oriented['ɔbdʒiktˌ-'ɔːrientid]adj.面向对象的Wordsself-sufficient['selfsə'fiʃənt]adj.自给自足的formula['fɔːmjulə]n.公式attribute[ə'tribju:t]n.属性variable['vεəriəbl]n.变量encapsulation[inˌkæpsə'leiʃən]n.封装accelerate[əkˌselə'reit]v.加速event-driven[i'vent-drivən]adj.事件驱动的superfluous[sju'pəːfluəs]adj.多余的prototype['prəutətaip]n.原型novice['nɔvis]n.初学者tag[tæg]n.标签horizontal['hɔri'zɔntəl]adj.水平的hyperlink['haipəliŋk]n.超链接Wordstemplate['templit]n.模板eliminate[i'limineit]v.消除bytecode[bitiː'kəud]n.字节代码plug-in['plʌg-ˌin]n.插件descriptive[di'skriptiv]adj.描述型的pinpoint['pinpɔint]v.精确地找到default[di'fɔːlt]n.默认；系统设定值interchange[ˌintə'tʃeindʒ;'intətʃeindʒ]n.互换PhrasesPhrasesasequenceof 一系列的computerprogramming 计算机编程softwareengineering 软件工程naturallanguage 自然语言assemblylanguage 汇编语言useup 耗尽codestatement 代码语句beproneto 易于……；有……的倾向procedurallanguage 过程语言reportgenerator 报告生成程序querylanguage 查询语言intermsof 在……方面；根据……speedup 加速gaspedal 油门inrelationto 关于；涉及classhierarchy 类层次结构visualprogramming 可视化编程Webprogramming 网页编程Webpage 网页authoringlanguage 编辑语言texteditor 文本编辑器fillout 填写runtimeenvironment运行时环境scriptinglanguage 脚本语言scrollingmessage 滚动信息site-specificbrowser 特定站点浏览器desktopwidget 桌面小工具PhrasesAbbreviationsAbbreviationsSQL 结构化查询语言(StructuredQueryLanguage)OOP 面向对象的程序设计(Object-orientedProgramming)RAD 快速应用软件开发(RapidApplicationDevelopment)WWW 万维网(WorldWideWeb)HTML 超文本标记语言(HypertextMarkupLanguage)VM 虚拟机器(VirtualMachine)XML 可扩展标记语言(ExtensibleMarkupLanguage)W3C 万维网联盟(WorldWideWebConsortium)NotesNotes

Whileitispossibletowriteprogramsdirectlyinmachinelanguages,itistediousanderrorpronetomanageindividualbitsandcalculatenumericaladdressesandconstantsmanually.本句中，While引导让步状语从句，表示“虽然……”,主句中it为形式主语，真正的主语为tomanageindividualbitsandcalculatenumericaladdressesandconstantsmanually。errorprone的意思为“易出错的”，短语beproneto表示“易于，倾向于”，通常含有贬义。

译文：虽然能直接用机器语言编写程序，但人工处理字节的每个位和计算数字地址和常量实在是单调乏味且容易出错。01Notes

Generally,assemblylanguagesareintermediatelanguagesthatareveryclosetomachinelanguagesanddonothavetheleveloflinguisticsophisticationexhibitedbyotherhigh-levellanguages,butmuststillbetranslatedintomachinelanguages.本句为一个并列复合句，thatareveryclosetomachinelanguages是一个定语从句，修饰和限定intermediatelanguages，过去分词短语exhibitedbyotherhigh-levellanguages修饰linguisticsophistication。

译文：总体而言，汇编语言是一种非常接近机器语言的中间语言，其虽不像其他高级语言那般复杂，但仍需被译为机器语言。02Notes

Theyrequirethattheprograminstructionstellthecomputerwhattoaccomplishandhowtodoit.本句中，that引导宾语从句theprograminstructionstellthecomputerwhattoaccomplishandhowtodoit。注意：require后的宾语从句需用虚拟语气，故从句中的谓语为(should)tell。03Notes

Currentlythoughthefourth-generationlanguagedoesimprovetheproductivityofprogramming,itmaynotentirelyreplacethethird-generationlanguagebecauseitisusuallyfocusedonspecifictasksandhenceoffersfeweroptions.

本句中，在though引导的让步状语从句中用do/does/did+动词原形的结构表示强调，“的确，确实”。

译文：目前，虽然第四代语言确实提高了编程效率，但它可能不会完全取代第三代语言，因为它通常着重于特定任务，可选择余地较小。04Notes

Simula67：Simula67被认为是最早的面向对象程序设计语言，它引入了所有后来面向对象程序设计语言所遵循的基础概念：对象、类、继承。它由挪威科学家Ole-JohanDahl和KristenNygaard发布，于1968年2月形成正式文本。Simula67的面向对象概念对编程语言的发展具有深远影响。0506

markuplanguage：标记语言，也称置标语言，是一种将文本（text）以及文本相关的其他信息结合起来，展现出关于文档结构和数据处理细节的电脑文字编码。与文本相关的其他信息（包括例如文本的结构和表示信息等）与原来的文本结合在一起，但是使用标记（markup）进行标识。当今广泛使用的置标语言是HTML和XML。置标语言广泛应用于网页和网络应用程序。Notes

scriptinglanguage：脚本语言，是为了缩短传统的编写-编译-链接-运行过程而创建的计算机编程语言。一个脚本通常是解释执行而非编译，其代码能够被实时生成和执行。脚本语言通常都有简单、易学、易用的特性，目的就是希望能让程序员快速完成程序的编写工作。07ExerciseExerciseExplainthefollowingabbreviations.1OOP1234WWWHTMLRAD面向对象的程序设计(Object-orientedProgramming)快速应用软件开发(RapidApplicationDevelopment)计算机辅助制造(Computer-aidedManufacturing)数据库管理系统(DatabaseManagementSystem)ExerciseExplainthefollowingabbreviations.1VM5678W3CXMLSQL 虚拟机器(VirtualMachine)结构化查询语言(StructuredQueryLanguage)可扩展标记语言(ExtensibleMarkupLanguage)万维网联盟(WorldWideWebConsortium)ExerciseFillineachblankwithasuitabletermoraphraseaccordingtoitsdefinition.201_____________:aninterpretedscriptinglanguagethatallowsWebauthorstoaddfunctionalitytotheirWebpages02__________________________:artificiallanguagesusedtowriteasequenceofinstructionsthatcanberunbyacomputer03______:aprogrammingmethodthatcombinesdataandinstructionsforprocessingthatdataintoanobjectJavaScript programminglanguageOOPExerciseFillineachblankwithasuitabletermoraphraseaccordingtoitsdefinition.204________________:aconceptofpackagingmethodsandattributesintoasingleobject05__________________:theprocessofwriting,testing,andmaintainingthesourcecodeofcomputerprograms06_________:abasicmarkuplanguagefordefiningthestructureandlayoutofaWebpageencapsulationprogrammingHTMLExerciseDecidewhetherthefollowingstatementsaretrueorfalse.3BasicconceptsofOOPincludeclassesandobjects.Assemblylanguagesarehigh-levellanguages.Byusingatexteditor,youcancreateabasicWebpage.TF(Assemblylanguagesarel