新东方网英语四级频道为大家整理了英语四级阅读练习,希望对大家备考英语四级有帮助
Paper--MorethanMeetstheEye
A)Wearesurroundedbysomuchpaperandcardthatitiseasytoforgetjusthowcomplexitis.Therearemanyvarietiesandgradesofpapermaterials,andwhilstitisfairlyeasytospotthevarieties,itisfarmoredifficulttospotthegrades.
B)Itneedstobeunderstoodthatmostpaperandcardismanufacturedforaspecificpurpose,sothatwhilstthecorn-flakepacketmaylooksmart,itisclearlynotsomethingdestinedforthearchives.Itismadetolookgood,butonlyneedsalimitedlifespan.Itisalsomuchcheapertomanufacturethanhighgradecard.
C)Papercanbemadefromanalmostendlessvarietyofcellulose-basedmaterialwhichwillincludemanywoods,cottonsandgrassesorwhichpapyrusisanexampleandfromwherewegettheword"paper".Manyoftheseareveryspecialized,butthepreponderanceofpapermakinghasbeenfromsoftwoodandcottonorrags,withthebulkbeingwood-based.
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.
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.
文章精要:
本文主要介绍了我们平常所见所用的纸的复杂性,通过介绍用木头和破布料造纸的过程,使我们对纸的类别、属性有了更深入的了解。
1.B根据题干中的信息提示词corn—flakepacket,highgradecard,可定位到文章第二段,该部分最后提到corn-flakepacket在制造过程中比高等级的纸(highgradecard)便宜.
2.C根据题干中的信息提示词softwood,cottonandrags,可定位到文章第三段最后一句。
3.D根据题干中的信息提示词finalproduct,可将答案定位到D段,第二、三句提到最后的产品来源于纤维素纸浆。
4.D根据题干中的信息提示词whitepaperandcard,可将答案定位到D段,该部分最后提到为了得到白纸,纸张生产者在制造过程中添加了漂白粉和其他化学物质。
5.E根据题干中的信息提示词essentialforthetree,可将答案定位到E段,该部分提到木质素是木头的主要组成物,其作用是凝聚纤维素,但它会使纸张变得易碎。
6.F根据题干中的信息提示词lignin,可将答案定位到F段,该部分最后提到许多纸张生产者在生产过程中会保留木质素,主要是因为它会增加树木的造纸产量。
7.G根据题干中的信息提示词acid,可将答案定位到G段,该部分最后提到酸对相纸的原料尤其不利。
8.F根据题干中的信息提示词lignin和paper可定位到文章的F段,因为该段提到,如果在纸张的生产中去除木质素,将会降低树木出产纸张的量,由此可以知道,去除了木质素的纸张价格必定会更加昂贵。
9.K根据题干中的信息提示词cottonandragwaste可定位到文章的K段,该部分告诉我们,尽管用棉花和破布料造的纸里没有木质素,但它们要比木制的纸贵很多,这是因为棉花和破布料的数量比树木少得多,由此可以得出答案。
10.M根据题干中的信息提示词PaperfromRa9可定位到文章的最后一段,该部分提出最好到专业的供应商那里去买档案材料,由此可以得出答案。
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