下面是新东方网考研频道英语四级频道为大家整理的英语四级阅读段落练习题,希望可以为大家带来帮助。
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2016年12月大学英语四级阅读段落练习题(1)思维导图模板大纲
下面是新东方网考研频道英语四级频道为大家整理的英语四级阅读段落练习题,希望可以为大家带来帮助。
Directions:Inthissection,youaregoingtoreadapassagewithtenstatementsattachedtoit.Eachstatementcontainsinformationgiveninoneoftheparagraphs.Identifytheparagraphfromwhichtheinformationisderived.Youmaychooseaparagraphmorethanonce.Eachparagraphismarkedwithaletter.
长篇阅读
A)Wearesurroundedbysomuchpaperandcardthatitiseasytoforgetjusthowcomplexitis.Therearemanyvarietiesandgradesofpapermaterials,andwhilstitisfairlyeasytospotthevarieties,itisfarmoredifficulttospotthegrades.
B)Itneedstobeunderstoodthatmostpaperandcardismanufacturedforaspecificpurpose,sothatwhilstthecorn-flakepacketmaylooksmart,itisclearlynotsomethingdestinedforthearchives.Itismadetolookgood,butonlyneedsalimitedlifespan.Itisalsomuchcheapertomanufacturethanhighgradecard.
C)Papercanbemadefromanalmostendlessvarietyofcellulose-basedmaterialwhichwillincludemanywoods,cottonsandgrassesorwhichpapyrusisanexampleandfromwherewegettheword"paper".Manyoftheseareveryspecialized,butthepreponderanceofpapermakinghasbeenfromsoftwoodandcottonorrags,withthebulkbeingwood-based.
PaperfromWood
D)Inordertomakewoodintopaperitneedstobebrokendownintofinestrands.Firstlybypowerfulmachineryandthenboiledwithstrongalkaliessuchascausticsoda,untilafinepulpofcellulosefibersisproduced.Itisfromthispulpthatthefinalproductismade,relyingonthebondingtogetherofthecelluloseintolayers.That,inaverysmallnutshell,istheessenceofpapermakingfromwood.However,therealityisrathermorecomplicated.Inordertogiveusourwhitepaperandcard,themakerswilladdbleachandothermaterialssuchaschinaclayandadditionalchemicals.
E)Afurtherproblemwithwoodisthatitcontainsamaterialthatisnotcellulose.Somethingcalledlignin.Thisisessentialforthetreesinceitholdsthecellulosefibrestogether,butifitisincorporatedintothemanufacturedpaperitpresentsarchivistswithaproblem.Lignineventuallybreaksdownandreleasesacidproductsintothepaper.Thiswillweakenthebondbetweenthecellulosefibersandthepaperwillbecomebrittleandlookratherbrownandcareworn.Wehaveallseenthisinoldnewspapersandcheappaperbackbooks.Ithasbeenestimatedthatmostpaperbackbookswillhavealifeofnotgreaterthanfiftyyears.Notwhatweneedforourarchives.
F)Sincethelignincanberemovedfromthepaperpulpduringmanufacture,theobviousquestionis"whyisitleftinthepaper?"Theanswerliesinthefactthatligninmakesupaconsiderablepartofthetree.Byleavingthelignininthepulpapapermakercanincreasehispaperyieldfromatreetosome95%.Removingitmeansayieldofonly35%.Itisclearlyuneconomictoremovetheligninformanypaperandcardapplications.
G)Italsomeans,ofcourse,thatlignin-freepaperisgoingtobemoreexpensive,butthatisneverthelesswhatthearchivistmustlookforinhissupplies.Thereisnopointwhatsoeverincarefullyplacingourvaluableartifactsinpaperorcardthatisgoingtohastentheirdemise.Acidisparticularlyharmfultophotographicmaterials,causingthemtofadeandissomecasessimplyvanish!
H)So,howdowetellapieceofsuitablepaperorcardfromonethatisunsuitable?Youcannotdoitbysimplylooking,andratherdisappointingly,youcannotalwaysrelyonthelabel."Acid-free"mightbetrueinasmuchasatestonthepapermayindicatethatitisaneutralmaterialatthistime.Butlignincantakeyearsbeforeitstartstheinevitableprocessofbreakingdown,andintherightconditionsitwillspeedupenormously.
I)Addedtothis,asIhaveindicatedearlier,papermayalsocontainothermaterialsaddedduringmanufacturesuchasbleach,chinaclay,chemicalwhitenersandsize.Thislookslikeableakpicture,anditwouldbebutforthefactthattherearesupplierswhowillguaranteethematerialthattheysell.Ifyouwanttobeabsolutelysurethatyouarestoringin,orprintingon,thecorrectmaterialthenthisisprobablytheonlyway.
J)Incidentally,acidscanmigratefrommaterialtomaterial.Liningoldshoeboxeswithgoodqualityacid-freepaperwilldolittletoguardthecontents.Theacidwillgetthereintheend.
PaperfromRag
K)Paperisalsocommonlymadefromcottonandragwaste.Thishastheadvantageofbeinglignin-free,butbecausethereismuchlesscottonandragthantrees,italsotendstobemuchmoreexpensivethanwoodpulppaper.Youwillstillneedtopurchasefromareliablesourcethough,sinceevenragpaperandcardcancontainundesirableadditives.
L)Areliablesourceforqualityragpapersisarecognizedartstockiest.Manywatercolorartistsinsistonusingonlyfinequalityragpaperandboard.
M)Themainlessontolearnfromthisinformationisthatyoucannotrelyonpurchasingarchivalmaterialsfromthehighstreet.Theonlysafesolutionistopurchasefromspecialistsuppliers.Itmaycostrathermore,butintheendyouwillknowthatyourimportantandvaluabledataandimageshavethebesthomepossible.
1.Thecorn-flakepacketischeaperthanhighgradecard.
2.Therearealotofmaterialswhichcanbeusedformakingpaper,butthesuperiorityonesaresoftwood,cottonandrags.
3.Duringthewholemanufacturingprocess,thefinalproductismadefromapulpofcellulosefibres.
4.Inordertomakewhitepaperandcard,themakerswilladdbleach.
5.Liguinisessentialforthetreebutitwillmakepapereasytobreak.
6.Manypaperproducerswillpreserveligninduringmanufacture,becauseleavingtheligninwillmakemorepaperfromatree.
7.Acidisparticularlyharmfultophotographicmaterials.
8.Iftheligninisremovedfromthepaper,thepaperwillbemoreexpensive.
9.Althoughfreeoflignin,papermadefromcottonandragwastecanalsocostmoremoneythanwoodpulppaperbecausethereismuchlesscottonandragthantrees.
10.Whatwecanlearnfrom"PaperfromRag"isthatyouhadbetterbuyarchivalmaterialsfromspecialistsuppliers.
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