大学英语四级练习T4三Word文件下载.docx

大学英语四级练习T4三Word文件下载.docx

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Papercanbemadefromanalmostendlessvarietyofcellulose-basedmaterialwhichwillincludemanywoods,cottonsandgrassesorwhichpapyrusisanexampleandfromwherewegettheword“paper”.Manyoftheseareveryspecialized,butthepreponderanceofpapermakinghasbeenfromsoftwoodandcottonorrags,withthehulkbeingwood-based.

PaperfromWood

Inordertomakewoodintopaperitneedstobebrokendownintofinestrands.Firstlybypowerfulmachineryandthenboiledwithstrongalkaliessuchascausticsoda,untilafinepulpofcellulosefibersisproduced.Itisfromthispulpthatthefinalproductismade,relyingonthebondingtogetherofthecelluloseintolayers.That,inaverysmallnutshell,istheessenceofpapermakingfromwood.However,therealityisrathermorecomplicated.Inordertogiveusourwhitepaperandcard,themakerswilladdbleachandothermaterialssuchaschinaclayandadditionalchemicals.

Afurtherproblemwithwoodisthatitcontainsamaterialthatisnotcellulose.Somethingcalledlignin.Thisisessentialforthetreesinceitholdsthecellulosefibrestogether,butifitisincorporatedintothemanufacturedpaperitpresentsarchivistswithaproblem.Lignineventuallybreaksdownandreleasesacidproductsintothepaper.Thiswillweakenthebondbetweenthecellulosefibersandthepaperwillbecomebrittleandlookratherbrownandcareworn.Wehaveallseenthisinoldnewspapersandcheappaperbackbooks.Ithasbeenestimatedthatmostpaperbackbookswillhavealifeofnotgreaterthanfiftyyears.Notwhatweneedforourarchives.

Sincethelignincanberemovedfromthepaperpulpduringmanufacture,theobviousquestionis“whyisitleftinthepaper?

”Theanswerliesinthefactthatligninmakesupaconsiderablepartofthefree.Byleavingthelignininthepulpapapermakercanincreasehispaperyieldfromatreetosome95%.Removingitmeansayieldofonly35%.Itisclearlyuneconomictoremovetheligninformanypaperandcardapplications.

Italsomeans,ofcourse,thatlignin-freepaperisgoingtobemoreexpensive,butthatisneverthelesswhatthearchivistinsistlookforinhissupplies.Thereisnopointwhatsoeverincarefullyplacingourvaluableartifactsinpaperorcardthatisgoingtohastentheirdemise.Acidisparticularlyharmfultophotographicmaterials,causingthemtofadeandissomecasessimplyvanish!

So,howdowetellapieceofsuitablepaperorcardfromonethatisunsuitable?

Youcannotdoitbysimplylooking,andratherdisappointingly,youcannotalwaysrelyonthelabel.“Acid-free”mightbetrueinasmuchasatestonthepapermayindicatethatitisaneutralmaterialatthistime.Butlignincantakeyearsbeforeitstartstheinevitableprocessofbreakingdown,andintherightconditionsitwillspeedupenormously.

Addedtothis,as1haveindicatedearlier,papermayalsocontainothermaterialsaddedduringmanufacturesuchasbleach,chinaclay,chemicalwhitenersandsize.Thislookslikeableakpicture,anditwouldbebutforthefactthattherearesupplierswhowillguaranteethematerialthattheysell.Ifyouwanttobeabsolutelysurethatyouarestoringin,orprintingon,thecorrectmaterialthenthisisprobablytheonlyway.

Incidentally,acidscanmigratefrommaterialtomaterial.Liningoldshoeboxeswithgoodqualityacid-freepaperwilldolittletoguardthecontents.Theacidwillgetthereintheend.

PaperfromRag

Paperisalsocommonlymadefromcottonandragwaste.Thishastheadvantageofbeinglignin-free,butbecausethereismuchlesscottonandragthantrees,italsotendstobemuchmoreexpensivethanwoodpulppaper.Youwillstillneedtopurchasefromareliablesourcethough,sinceevenragpaperandcardcancontainundesirableadditives.

Areliablesourceforqualityragpapersisarecognizedartstockiest.Manywatercolorartistsinsistonusingonlyfinequalityragpaperandboard.

ThemainlessontolearnfromthisinformationisthatyoucannotrelyonpurchasingarchivalmaterialsfromthehighStreet.Theonlysafesolutionistopurchasefromspecialistsuppliers.Itmaycostrathermore,butintheendyouwillknowthatyourimportantandvaluabledataandimageshavethebesthomepossible.

1.Thecorn-flakepacketischeaperthan______

[A]highgradecard[C]lowgradecard

[B]middlegradecard[D]anygradecard

2.Therearealotofmaterialswhichcanbeusedformakingpaper,butthesuperiorityonesare

[A]woods,cottonsandgrasses[C]softwood,cottonandrags

[B]softwoodandcotton[D]cottonsandgrasses

3.Duringthewholemanufacturingprocess,diefinalproductismadefrom______

[A]strongalkalies[C]cellulosefibres

[B]causticsoda[D]apulpofcellulosefibres

4.Inordertomakewhitepaperandcard,themakerswilladd_____.

[A]albescent[B]bleach[C]escharotic[D]lysozyme

5._____isessentialforthetreebutitwillmakepapereasytobreak.

[A]Acid[B]Alkali[C]Cellulosefibres[D]Lignin

6.Manypaperproducerswillpreserveligninduringmanufacture,because______

[A]leavingtheligninwilldecreasehispaperyield

[B]leavingtheligninwillmakemorepaperfromatree

[C]ligninisveryusefulintheprocess

[D]ligninisessentialformakingpaper

7._____isparticularlyharmfultophotographicmaterials.

[A]Lignin[B]Bleach[C]Acid[D]Chemicalwhiteners

8.Iftheligninisremovedfromthepaper,thepaperwillbemoreexpensive.

9.Althoughfreeoflignin,papermadefromcottonandragwastecanalsocostmoremoneythanwoodpulppaperbecausethereismuchlesscottonandragthantrees.

10.Whatwecanlearnfrom“PaperfromRag”isthatyouhadbetterbuyarchivalmaterialsfromspecialistsuppliers.

PartIIIListeningComprehension（35minutes）

SectionA

11.[A]He’llbespeakingattheendofthemeeting.

[B]Hewassupposedtospeaklastnightinstead.

[C]Hesuddenlydecidednottospeak.

[D]Healreadyspokeverybrieflytonight.

12.[A]It’stoohigh.[B]It’sacceptable.

[C]It’scheapindeed.[D]Thewomanshouldhavebargainedforit.

13.[A]Attwoo’clock.[C]Atfouro’clock.

[B]Atthreeo’clock.[D]Atfiveo’clock.

14.[A]Shopassistantandcustomer.[C]Storekeeperandcustomer.

[B]Postclerkandcustomer.[D]Waitressandcustomer.

15.[A]Hisgirlfriendcomplainedofhisgoingtothepartywithouther.

[B]Hewastogetherwithhisgirlfriendyesterday.

[C]Hehasbeenbusydatinghisgirlfriendthesedays.

[D]Hebroughthisgirlfriendtotheparty.

16.[A]Sheregrettedhavingboughtthesecond-handcar.

[B]Itisunnecessarytorentanotherhouse.

[C]Theyshouldselltheirsecond-handcarandbuyanewone.

[D]Theycanaffordasecond-handcar.

17.[A]Shelovesthefilmtoo.[C]Sheasksthemantorepeathiswords.

[B]Shedoesn’tthinkmuchofthefilm.[D]It’snotasgoodassheexpected.

18.[A]Gooutwithhiswife.[C]Stayathomewithhiswife.

[B]Workforextrahours.[D]Gooutwithhisboss.

Questions19to22arebasedontheconversationyouhavejustheard.

19.[AIt’shereditary.[C]Hecombshishairtoomuch.

[B]Theshampooheusedcausedit.[D]Heisoldenoughtolosehair.

20.[A]Usesomespecialshampoo.[B]Wearawig.

[C]Don’ttrytocombhairoverthebaldorthinpatch.

[D]Gotothedoctorforadvice.

21.[A]Overtheradio.[C]Attheman’shouse.

[B]Atadoctor’soffice.[D]Atadrugstore.

22.[A]Itsuitshim.[C]Itlooksold.

[B]Itlooksridiculous.[D]It’sgettingworse.

Questions23to.25arebasedontheconversationyouhavejustheard.

23.[A]Onceaweek.[C]Fiveeverymonth.

[B]Threeeverymouth.[D]Twoeverymonth.

24.[AlWhentherearemorethantwelvepeople.[B]Whentherearefivepeople.

[C]Whentherearefifteenpeople.[D]Whentherearemorethanfifteenpeople.

25.[A]Calltheoffice.

[B]Signyournameonthenoticeboardinadvance.

[C]Paythemoney.[D]Thereisnoneedtoreserveaplace.

SectionB

PassageOne

26.[A]Becauseitisn’tclosed.

[B]Becausethestudentshavetopassallexaminationsbeforeenteringit.

[C]Becausethereisnoexaminationbeforetheyareacceptedasstudents.

[D]Becauseitsdoorisopen.

27.[A]Attheairport.[B]Byplane.[C]Takingtheair.[D]OnradioandTV.

28.[A]Four.[B]Eight.[C]Three.[D]Five.

29.[A]Infourorfiveyears.[C]Inthreeorfouryears.

[B]Inoneyear.[D]In36weeks.

PassageTwo

30.[A]Anewwaytotakenotes.[B]Ashortnameforsurveyreadingmethod.

[C]Thefivestepsinthereadingprocess.[D]Differentwaystostudyforexaminations.

31.[A]Thatoneshouldthinkabouttheideaswhilereadingthewords.

[B]Thatoneshouldalwaystakenotes.

[C]Thatoneshouldreadonlythetitleandimportantwords.

[D]Thatoneshouldreadsequencesofwords.

32.[A]Read.[B]Reci