2023年英語四級模擬

答題倒計時1:59:57固定倒計時框計時透明背景

模擬試卷考試時間：120分鐘

滿分：150分

英語四級新試題803PartI

Writing

Directions:Forthispart,youareallowed30minutestowriteAnOpeningSpeech.Youshouldwriteatleast120wordsfollowingtheoutlinegivenbelow:

1.

假設你的學校要召開運動會，你作為該校學生會的發(fā)言人在開幕式上發(fā)言，請寫一份開幕詞，涉及以下內(nèi)容：

1．表白自己的身份和發(fā)言的重要內(nèi)容；

2．對到場的領導和老師給予的支持表達感謝，并闡述做體育運動的益處；

3．預祝本次運動會取得圓滿成功。

AnOpeningSpeech

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PartII

ReadingComprehension(SkimmingandScanning)

Directions:Inthispart,youwillhave15minutestogooverthepassagequicklyandanswerthequestionsonAnswersheet1.

Forquestions,mark

Y(forYES)

ifthestatementagreeswiththeinformationgiveninthepassage;

N(forNO)

ifthestatementcontradictstheinformationgiveninthepassage;

NG(forNOTGIVEN)

iftheinformationisnotgiveninthepassage.

Forquestions,completethesentenceswiththeinformationgiveninthepassage.

ImpactofMediaonDistanceEducation

Mediaiseverywhere;ithasbecomeapartofourdailylife.Themediaplaysadominantroleinthelearningprocessandhasopenednewdimensionsinlearning.Noweducationisnolongeraconstraint(約束)foranyone.Mediahasbroughteducationtothedoorstepofeachandeveryindividual.Allformsofmedia—thenewspaper,radio,televisionandtheInternetareequallyimportantinimpartingeducation.Asthetechnologyisprogressing,thedifferenteducationalmodules(模塊)arebeingchanneledthroughcertaincommunityaccesscenterslikecommunityradiosystem,televisions,internet,communitymulti-mediacenters,etc.Medialiteracyoreducationdoesnotonlymeantobeentertainedbymediabuttolearnsomethingfromit.

Distanceeducationisoftendefinedasinstitution-based,formaleducationwherethelearninggroupisseparate,andwhereinteractivetelecommunicationssystemsareusedtoconnectlearners,resources,andinstructors.

Theoriginaldistanceeducationbycorrespondencehasbeenupgradedbytwenty-firstcenturytechnology.Distanceeducationhasvastlybenefitedfromthemediaboomwithtelecastsandbroadcastslimitingthedependenceonthewrittenword.Inthepast,distanceeducationwasprimarilydeliveredthroughmailandwascalledcorrespondencecourse.Themediumofinstructionwasmainlythroughbooks,paperdocumentsandotherprintedmaterials.Contrarytoclassroomlearning,instructionsprovidedbyprofessorsorteachersweredeliveredinprinttothelearnerswhodidn'thavetheopportunitytohaveinteractiveclasses.Queriesandnoteswereinterchangedbetweenteachersandstudentsandviceversa.

Butnowthetrendisfullyreplacedbycolourfulcomputer-basedgraphicresources.Computer-basededucationhaschangedthetraditionalofferingsofcorrespondenceeducation.Thismediumofeducationconvertsthetraditionalstaticresourcesintointeractiveandinterestingonlinemodulesforthelearners.Moreover,online-learningretainsmostofthecharacteristicsoftheclassicalformofdistancelearning,whileofferingmoresophisticatedlearningmaterialsatamuchreducedrate.

Atpresent,theconceptofdistanceeducationwiththehelpofmediahasgainedwidepopularity.Themediaboomwithtelecastsandbroadcastshastoalargeextentlimitedthedependenceonthewrittenword.Moreover,withtheemergenceoftheInternetasaglobalmedia,theconceptofdistancelearninghasbeenrevolutionized.Fromtheage-olddays,distancelearningwasmainlyprovidedthroughcorrespondence.ButtheintroductionoftheInternethaschangedtheconceptofdistancelearningtoagreatextent.

Nowadays,distancelearningprogrammesareincreasinglybeingdeliveredthroughcomputertechnologiesbutthetraditionalmediaisnottotallyuselessasithelpsineffectivelearning.Wecandefinequalityonlineeducationasapeople-oriented,instructor-ledactivity,wherethelevelofcommunicationshouldbecomparablewithon-campuseducation.DuetotheconnectivityoftheInternet,distanceeducationisoftencalledonlinelearningbecausetheInternet-connectedcomputersbringtheteacherandlearnerfacetoface,whichsubstitutes/replacesclassroomlearning.Moreover,theInternethasalsofacilitatedthestudentstostudyonlinefromanylocationandatanyconvenienttime.

Therearenumerousfactorswhichhavecontributedtotheincreasingpopularityofthedistanceeducationthroughmedia.Withtheintroductionofonlinelearninginuniversities,distancelearninghasgainedimmenseimportance.Onlinelearninghasassumedtheroleofanimportantmediaforimpartingdistanceeducation.Italsowenttotheextentofprovidingqualityonlinecourseswhichhavebecomealmostcomparabletothetraditionalclassroomlearning.Nowstudentscangetaccesstoabroadrangeofdisciplinesfromanylocation.Withtheminglingofonlinelearninganddistanceeducation,educationisnolongeraconstraintforanyclassofthesociety.

DistanceeducationcanalsobetermedasInteractiveTelecommunicationssystem.Interactivetelecommunicationssystemsbroadlymeanthattheinstructorsandthelearnersuseavarietyoftechnologicalresourceswhileteachingandlearningfromadistance.Nowadays,manyuniversitieshavecomeupwiththeideaoftransferringitson-campuslearningintoonlinelearning.

Nowweseeanexcessiveuseofmediaineducation.Mediahasmadeitspresencefelteverywhere,beitbytelevision,radioorcomputers,themostpopularmediumofimpartingeducation.Unlikethepast,educationandexaminationisnolongermonotonous(乏味的).Withtheintroductionofmedia,educationhasassumedadifferentrole.Wecanseethatbeforetheboardexamsoranycompetitiveexams,differentmediasliketelevision,radio,eoutwithdifferenteducation-relatedprogramstohelpstudentstodealwiththeirstudymaterials.Thesemediachannelsropeindifferentintellectuals,professorsandteachersofdifferentinstitutionstoguidethestudentswiththeirvaluablesuggestionsandgivethemnecessarymoralboosttocopeupwiththeirburdenofstudies.

Themostimportantadvantageofonlinedistanceeducationistoearnadegreefromone'shomeorworkplace.Intraditionaldistancelearning,interactionislimitedtoacertainpointandfeedbackfromtheothersideisoftendelayedbecauseofslowpostalsystems.Ithashelpedalargenumberofpeopletopursueeducation,whodon'tevenhavethetimetoenrollforregularcourses.Moreover,itisusuallyeasierandlesscompetitivetoobtainadmissionfortheonlinecourses.

Incaseofonlinedistancecourses,learningismorefunandinteractive.Itisalsoflexible.Itispossibletoincorporatecharts,maps,graphs,movingimages,slides,videoclippingsandevenaudiorecordingswiththecoursematerial.Ithelpstounderstandtheentiresyllabuswithoutthehelpofateacher.Thestudentsareabletointeractwiththeirpeersthroughonlineclassprojects,e-mailsandalsowiththehelpofonlineconferencing.Thisinteractionwiththehelpofmediausinge-mail,conferencecallsandchatmakeslearningeasierandentertaining.Itsubstitutestheface-to-faceexperiencesoftraditionallearning.Theavailabilityofonlinelibrarieswiththeirhugecollectionofbookshasalsomadethelearningprocesseasierandworthwhile.

Speakingabouttheeconomicsideofonlinedistancelearning,itisseenthatmostofthetime,theexpenseofaregularcourseismuchhigherthantheonlinecourses.Themedia-relatedonlinedistancelearningisrelativelyeconomicalthanthetraditionalclass-roomlearning.Nevertheless,keepinginminditspositiveeffectsonindividuals,thesecomputer-baseddistanceeducationcontinuestogrow.1.Accordingtotheauthor,educationissuretobelimitedtoacertainscopewithouttheuseofmedia.[A]

Y[B]

N[C]

NG2.Correspondencecoursewasthemajorformofdistanceeducationinthepastwiththeteachingbeingfulfilledthroughmail.[A]

Y[B]

N[C]

NG3.Computer-basededucationhastakenplaceofcorrespondencecoursebecauseitofferscolorfulpicturesaswellaswords.[A]

Y[B]

N[C]

NG4.Theappearanceofdistancelearningproducesabigeffectonthesocietyandleadstotherevolutionofawholeage.[A]

Y[B]

N[C]

NG5.WiththeuseoftheInternet,thetraditionalmediahasbeenoutofdatebecauseofitsineffectivenessindistanceeducation.[A]

Y[B]

N[C]

NG6.Nowstudentshaveavarietyofcoursechoiceswhenregisteringforanonlinelearningnomatterwheretheyare.[A]

Y[B]

N[C]

NG7.Interactiveonlinelearningcartberealizedwhenteachersandstudentsusetechnologicalresourcesineducation.[A]

Y[B]

N[C]

NG8.Instructorsfromdifferentinstitutionscanbeintegratedasawholetoofferstudentsbothacademicsuggestionsandcourageon______.

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[=]9.Unliketraditionaldistancelearning,onlinelearningdoesn'tusepostalsystem,thereforecanavoid______.

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[=]10.Studentscanturntomethodssuchasonlineclassprojects,e-mailsandonlineconferencingtofulfill______.

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PartⅢ

ListeningComprehension

SectionA

Directions:Attheendofeachconversation,oneormorequestionswillbeaskedaboutwhatwassaid.Boththeconversationandthequestionswillbespokenonlyonce.Aftereachquestiontherewillbeapause.Duringthepause,youmustrendthefourchoicesmarked[A]、[B]、[C]and[D],anddecidewhichisthebestanswer.ThenmarkthecorrespondingletteronAnswerSheet2withasinglelinethroughthecentre.

Questions11to18arebasedontheconversationyouhavejustheard.

點擊此處播放11.[A]

Hewasofferedamovieticket.[B]

Hereceivedatrafficticket.[C]

Heworksverycarefully.[D]

Healwaysdrivescarelessly.12.[A]

Sheprefersapplesfordessert.[B]

Shewantstohavesomeoranges.[C]

Shedoesn'twanttohavedessert.[D]

Sheprefersbananasfordessert.13.[A]

Helikestheblackandwhitesweater.[B]

Hedoesn'tlikeeither.[C]

Helikesthewhitedress.[D]

Helikesallofthem.14.[A]

Heneedsalong-sleevedshirt.[B]

Itdoesn'tfithimverywell.[C]

Hehasn'thadtimetotryitonyet.[D]

Heisnotsurehelikesthestyle.15.[A]

Thewomandidhershareindoingthejob.[B]

Thewomandidnothelptohelpfulfilltheplan.[C]

Themantookforgrantedthewoman'shelp.[D]

Themandoesn'tthankthewomanforherhelp.16.[A]

Shedoesn'tliketogoshopping.[B]

Shepreferredshoppingtostudying.[C]

Shedoesn'tlivenearshops.[D]

Shewentshoppingyesterday.17.[A]

Shelikesthefirstonethoughitisexpensive.[B]

Shedoesn'tlikebothofthem.[C]

She'sgoingtochoosethecheaperonetosavemoney.[D]

Shepreferstheexpensiveonewithlessmaintainingcost.18.[A]

Theapplesaredelicious.[B]

Theapplesmightnotbesogood.[C]

Theapplesarenotintheseason.[D]

Theapplesareverygood.

Questions19to21arebasedontheconversationyouhavejustheard.

點擊此處播放19.[A]

Heusesitforhisjob.[B]

Hespendstoomuchtimeonthebus.[C]

Helivestoofarfromtheuniversity.[D]

Hewouldfeelsaferatnightwithacar.20.[A]

Askaboutthemile-age.[B]

Avoidbuyinganoldear.[C]

Getamechanicalinspection.[D]

Checktheservicerecords.21.[A]

Heisanexpertofcarsales.[B]

Heisamechanicofcars.[C]

Heistheowneroftheear.[D]

Heisaninspector.

Questions22to25arebasedontheconversationyouhavejustheard.

點擊此處播放22.[A]

Inashoptoday.[B]

Inastreettoday.[C]

Inthestreetyesterday.[D]

Inashopyesterday.23.[A]

Itsoldsportshoesnearabank.[B]

Itsoldsportshoesbutsoonwentbankrupt.[C]

Itsoldsportsuitsnearabank.[D]

Itsoldsportsuitsbutsoonwentbankrupt.24.[A]

Becausehisbeerwasnotfine.[B]

Becausehesoldharddrinks.[C]

Becausehesoldbeer.[D]

Becausehisharddrinkswerenotfine.25.[A]

Somepeopledidn'tsupporthim.[B]

Somepeoplearejealousofhim.[C]

Hiswifewantedhimtogiveuphisbusiness.[D]

Hehasnoconfidencetorunhisbusinessanymore.

SectionB

Directions:Inthissection,youwillhear3shortpassages.Attheendofeachpassage,youwillhearsomequestions.Boththepassageandthequestionswillbespokenonlyonce.Afteryouhearaquestion,youmustchoosethebestanswerfromthefourchoicesmarked[A]、[B]、[C]and[D].ThenmarkthecorrespondingletteronAnswersheet2withasinglelinethroughthecentre.

Questions26to28arebasedonthepassageyouhavejustheard.

點擊此處播放26.[A]

Takewiththemagiftforthehost.[B]

Takewiththemagiftforthehost'schildren.[C]

Takewiththemagiftforthehost'swife.[D]

Takewiththemagiftforeveryoneofthehost'sfamily.27.[A]

Agiftofmoney.[B]

Agiftshowingappreciation.[C]

Fruitsfortheentirefamily.[D]

Sweetsforthechildren.28.[A]

Onweekendparty.[B]

Onbirthdayparty.[C]

Onovernightparty.[D]

Onthewedding.

Questions29to31arebasedonthepassageyouhavejustheard.

點擊此處播放29.[A]

Becauseallthebuildingsinthecitylookalike.[B]

Becausetherearenosignstodirectthem.[C]

Becausenotourguidesareavailable.[D]

Becausetheuniversityiseverywhereinthecity.30.[A]

Theyawardtheirowndegrees.[B]

Theyselecttheirownstudents.[C]

Theysettheirownexams.[D]

Theyorganizetheirownlaboratorywork.31.[A]

Theywerenottreatedequallyuntil1881.[B]

Theywerenotawardeddegreesuntil1948.[C]

Theyhavenoexamsuntil1948.[D]

Veryfewofthemareengagedinresearch.

Questions32to35arebasedonthepassageyouhavejustheard.

點擊此處播放32.[A]

Ithasanegativeeffectonthenaturalenvironment.[B]

Thequalityofourlifeisdecreased.[C]

Theworld'spopulationisapproachingcertainlimitsongrowth.[D]

Naturalresourcesareusedup.33.[A]

Becauseitcancreatethecapitalneededtoimproveourqualityoflife.[B]

Becauseitcanprovidenaturalresourcestoindustry.[C]

Becauseitcanmakethequalityotlifedecrease.[D]

Becauseitcancontroltheworld'spopulation.34.[A]

Theadvantagesoftheeconomicgrowth.[B]

Thedisadvantagesoftheeconomicgrowth.[C]

Theimportanceoftheeconomicgrowth.[D]

Thedebateaboutwhethertheeconomicgrowthisdesirable.35.[A]

Theauthorisinfavorofeconomicgrowth.[B]

Theauthorisagainstcontinuedeconomicgrowth.[C]

Theauthordoesnotshowhispointofview.[D]

Theauthorisverygladtojointhediscussion.

SectionC

Directions:Inthissection,youwillhearapassagethreetimes.Whenthepassageisreadforthefirsttime,youshouldlistencarefullyforitsgeneralidea.Whenthepassageisreadforthesecondtime,youarerequiredtofillintheblanksnumberedfrom36to43withtheexactwordsyouhavejustheard.Forblanksnumberedfrom44to46youarerequiredtofillinthemissinginformation.Fortheseblanks,youcaneitherusetheexactwordsyouhavejustheardorwritedownthemainpointsinyouownwords.Finally,whenthepassageisreadforthethirdtime,youshouldcheckwhatyouhavewritten.

Advertisingisawayofbringing

(36)

tothepublicforthepurposeofsellingaproduct,aservice,anidea,oran

(37)

.Theinformationistransmittedbymeansof

(38)

wordorovertheair.Itmaybepresentedasasimple

(39)

offact,orasmoreoften,itmaybeofferedincolorfuloreven

(40)

language.Alladvertisingisintendedto

(41)

peopletodosomespecificthings,suchasbuyaproduct,orderaservice,joinanorganization,or

(42)

ameetingandsoon.Eachadvertisementispaidforbyaperson,agroup,anorganization,orabusiness

(43)

seekingtoadvancehisoritsgoals.

Inamodernsociety,everyoneusesadvertisinginonewayoranother.Apersonmayobtainajobbyansweringaclassifiedad,orsometimescalledasmallad.Itisplacedinanewspaperbythosewishingtosellorbuysomething,leaseorrentsomething,offerorgetemployment,etc.

(44)

.Inchoosingfoodproductsandotheritemsofdailyliving,heisusuallyguidedorinfluencedbyadvertising.

(45)

.

Advertisinghascertainlyplayed,animportantpartinmakingmoderngoodsandservicesavailabletothegeneralpublic,ithastenedcontainer'sacceptanceofsuchnewproductsascars,telephones,electricrefrigerators,andfrozenfoods.

(46)

.

點擊此處播放36.

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[=]39.

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[=]40.

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PartⅣReadingComprehension(ReadinginDepth)

SectionA

Directions:Inthissection,thereisapassagewithsomeblanks.Youarerequiredtoselectonewordforeachblankfromalistofchoicesgiveninawordbankfollowingthepassage.Readthepassagethroughcarefullybeforemakingyourchoices.

ThanksgivingisAmerica'snationalholidayforgivingthankstoGod.ThanksgivingDayhasaspecial

(47)

forAmericansbecauseitistracedbacktothatgroupofpeoplewhowereamongthefirsttocometotheNewWorldinsearchoffreedom.

In1620,102seaweary(疲倦的)PilgrimslandedonthepeninsulaofCapeCod.Theirship,theMayflower,had

(48)

togotoVirginia,butitmadeitslandfallfartothenorth.Aftersomeweeksof

(49)

theydecidednottomakethetriptoVirginiabuttoremainwheretheywere.Butwhentheysteppedashoreinthis

(50)

alienworld,theyweretotallyisolatedfromanyoutside

(51)

andknewnomeansoflivelihood.AndthegreatertroubleisthatinthewoodsliveIndians,someofwhomwere

(52)

.Thisaddedtothehardshipofdailylife.Butthevast

(53)

offorestsgavethemahope.Inthisway,thenation'sforefathersnotonly

(54)

thefirstseverewinter,butalsosawthefirstharvestofcropsinthenextautumn.TheirIndianfriendswerealsoinvitedtojointheirfestival.

ThisstoryistoldeveryyeartoyoungchildreninschoolsasThanksgivingDay(thefourthclayofNovember

(55)

.

Today,inUSThanksgivingDayiscelebratedbymanyAmericanswhoserootsdonotstemfromBritain.Nowitismarkedbyfamiliesgatheringtogethertoenjoya

(56)

dinnerforroastturkey,andtotellthethingsforwhichtheyarethankful.

A)

approaches

B)

hostile

C)

traditional

D)

justified

E)

stretches

F)

utterly

G)

survived

H)

assistance

I)

intended

J)

appropriate

K)

exploring

L)

structure

M)

significance

N)

interfered

O)

normally6.

SectionB

Directions:Thereare2passagesinthissection.Eachpassageisfollowedbysomequestionsorunfinishedstatements.Foreachofthemtherearefourchoicesmarked[A]、[B]、[C]and[D].YoushoulddecideonthebestchoiceandmarkthecorrespondingletteronAnswerSheet2withasinglelinethroughthecentre.

PassageOne

Desertification(沙漠化)inthedryUnitedStatesisveryserious.Groundwatersuppliesbeneathvaststretchesoflandaredroppingrapidly.Manyriversystemshavedriedup.Hundredsofthousandsofacresofpreviouslyirrigatedcroplandhavebeenabandonedtowindorweeds.Severalmillionacresofnaturalgrasslandareerodedatunnaturallyhighratesasaresultofcultivationorovergrazing(過度放牧).Alltold,about225millionacresoflandareunderseveredesertification.

Federalsubsidies(補貼)encouragetheexploitationofdrylandresources.Low-interestloansforirrigationandotherwaterdeliverysystemsencouragefarmersandindustrytominegroundwater.Federaldisasterreliefandcommodityprogramencouragedry-landfarmerstoplowupnaturalgrasslandtoplantcropssuchaswheat,especially,cotton.Federalgrazingfeesthatarewellbelowthefreemarketpriceencourageover-grazingofthecommons.Themarket,too,providespowerfulincentives(激勵)toexploitdrylandresourcesbeyondtheircarryingcapacity.

Theincentivestoexploitdrylandresourcesaregreaterthanever.Thegovernmentisnowofferinghugenewsubsidiestoproducesyntheticfuelfromcoaloilaswellasalcoholfuelfromcrops.Moreover,commoditypricesareontherise;andtheywillprovidefarmersandagriculturalbusinesseswithpowerfulincentivestooverexploitaridlandresources.Theexistingfederalgovernmentcost-shareprogramsdesignedtohelpfinancetheconservationassoil,water,andvegetationarepaleincomparisontosuchincentives.

Inthefinalanalysis,whenviewedinthenationalperspective,theeffectsonagriculturearethemosttroublesomeaspectofdesertificationintheUS.Foritcomesatatimewhenwearelosingoveramillionacresofrain-wateredcropandgrasslandperyeartohigheruses—shoppingcenters,industrialparks,housingdevelopment,andwastedump—regardlessoftheeconomicneedoftheUStoexportagriculturalproductsoroftheworld'sneedUSfoodandfiber.TodaythedryWestaccountsfor20percentofthenation'stotalagriculturaloutput.IftheUSis,asitappears,wellinitswaytowardoverdrawingthedrylandresources,thenthepolicychoiceissimplytopaynowfortheappropriateremediesorpayforlaterwhenproductivebenefitsfromaridlandresourceshavebeenbothrealizedandlargelyterminated.57.Whichofthefollowingismentionedasaresultofseveredesertification?[A]

Theshrinkingofforestcoverage.[B]

Thelackofwatersupplies.[C]

Aquicklydecreasingproductionofcrops.[D]

Alargeareaofcroplandchangedintograssland.58.Fromthesecondandthirdparagraphswelearnthat______.[A]

moregovernmentmoneyisbeingusedfreelytoprotectlandsfromdesertification[B]

theexploitationoftheexistingdrylandisagainstthemarket[C]

thefederalgovernmentfavorsfarmersalotoverworkersincompanies[D]

greatefforthasbeenmadebythegovernmenttomakeuseofdryland59.Whichofthefollowingistrueabouttheexistingfederalgovernmentcost-shareprograms?[A]

Itcostthefarmersalotofmoney.[B]

Itsmainaimistodevelopeconomy.[C]

Itissmallercomparedtothedrylandexploration.[D]

Itisveryeffectivetothedrylandexploration.60.Thehigherusesarecriticizedbytheauthorbecause______.[A]

boththeworldandAmericaneedthelandforagriculturalaims[B]

theybringaboutalargeamountofwasteofresources[C]

Americansdonotneedthatmanyshoppingcentersandapartments[D]

industrialparksandwastedumpsareseriouslypollutingtheenvironment61.Whatcanwelearnaboutthepolicychoiceinthelastsentence?[A]

It'sthebestwaytosolvethedesertificationinAmerica.[B]

It'sthewaywhichAmericaisundertakingnow.[C]

TheAmericanswillbenefitalotfromitinthefuture.[D]

It'sacostingandineffectivewaytosolvethedesertificationinAmerica.

PassageTwo

Nodocumentissafeanymore.Fakingoncethedomainofskilleddeceiversthatusedexpensiveengraving(雕刻)andprintingequipment,hasgonemainstreamsincethepriceofdesktop-publishingsystemshasdropped.Inancienttimes,fakingwasahangingoffence.Today,desktopcounterfeitershavelittlereasontoworryaboutprison,becausethesystemstheyuseareuniversalandthereisnomeansoftracingforgeddocumentstothemachinethatproducedthem.This,however,maysoonchangethankstotechnologydevelopmentbyGeorgeChiu,ananti-fakingengineer.

Hisapproachisbasedondetectingimperfectionsintheprintqualityofdocuments.Old-schoolcourtscientistswereabletotracedocumentstoparticulartypewritersbasedonquirks(溝槽)oftheindividualkeys.Heemploysasimilarapproach,exploitingthefactthattherotatingdrumsandmirrorsinsideaprinterareimperfectpiecesofengineeringwhichleaveuniquepatternsofbandingintheirproducts.

Althoughthesepatternsareinvisibletothenakedeye,theycanbedetectedandanalyzedbycomputerprograms,anditisthesethatDr.Chiuhasspentthepastyeardevising.Sofar,hecannottraceindividualprinters,buthecantellprettyreliablywhichmakeandmodelofprinterwasusedtocreateadocument.

That,however,isonlythebeginning.Whileitremainstobeseenwhetheritwillbepossibletotraceacounterfeitdocumentbacktoitsguiltycreatoronthebasisofmanufacturingimperfections,Dr.Chiuisnowworkingoutwaystomakethoseimperfectionsdeliberate.Hewantstomodifytheprintingprocesssothatunique,invisiblesignaturescanbeincorporatedintoeachmachineproducedwhichwouldmakenaydocumenttraceable.

Ironically,itwasafteryearsofcollaboratingwithprintingcompaniestoreducebandingandthusincreasethequalityofprints,thathecameupwiththeideaofintroducingartificialbandingthatcouldencodeidentificationinformationintoadocument.Usingthebandingpatternsofprinterstosecuredocumentswouldbebothcheaptoimplementandhard,ifnotimpossible,forthosewithoutspecialistknowledgeandhardwaretohideout.

Notsurprising,theAmericanSecretServiceismonitoringtheprogressofthisresearchveryclosely,andisprovidingguidelinestohelpDr.Chiutotravelinwhattheservicethinksistherightdirection,whichisfineforcatchingcriminals.ButhowthelegalusersofprinterswillreacttoBigBrotherbeingabletotrackanydocumentbacktohissourceremainstobeseen.62.Bysaying"nodocumentissafeanymore",theauthorprobablymeans______.[A]

affordableprintersmakeitpossibleforanyonetoforgedocuments[B]

theAmericanSecretServicewillbeabletotraceanydocument[C]

everyprinteddocumentwillbesecretlymarkedoutthroughhigh-tech[D]

counterfeitershavemoreadvancedtechnologytouse63.Whatliesatthecoreofbotholdandnewwaysofanti-fakingi