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1、xx年6月英语六级段落匹配题模拟题 小编为大家整理了xx年6月大学英语六级段落匹配练习题供广大考生备考使用希望能为大家带来帮助 PaperMorethanMeetstheEye A)Wearesurroundedbysomuchpaperandcardthatitiseasytoforgetjusthowplexitis.Therearemanyvarietiesandgradesofpapermaterials,andwhilstitisfairlyeasytospotthevarieties,itisfarmoredifficulttospotthegrades. B)Itneedstob
2、eunderstoodthatmostpaperandcardismanufacturedforaspecificpurpose,sothatwhilstthecornflakepacketmaylooksmart,itisclearlynotsomethingdestinedforthearchives.Itismadetolookgood,butonlyneedsalimitedlifespan.Itisalsomuchcheapertomanufacturethanhighgradecard. C)Papercanbemadefromanalmostendlessvarietyofcel
3、lulosebasedmaterialwhichwillincludemanywoods,cottonsandgrassesorwhichpapyrusisanexampleandfromwherewegetthewordpaper.Manyoftheseareveryspecialized,butthepreponderanceofpapermakinghasbeenfromsoftwoodandcottonorrags,withthebulkbeingwoodbased. PaperfromWood D)Inordertomakewoodintopaperitneedstobebroken
4、downintofinestrands.Firstlybypowerfulmachineryandthenboiledwithstrongalkaliessuchascausticsoda,untilafinepulpofcellulosefibersisproduced.Itisfromthispulpthatthefinalproductismade,relyingonthebondingtogetherofthecelluloseintolayers.That,inaverysmallnutshell,istheessenceofpapermakingfromwood.However,t
5、herealityisrathermoreplicated.Inordertogiveusourwhitepaperandcard,themakerswilladdbleachandothermaterialssuchaschinaclayandadditionalchemicals. E)Afurtherproblemwithwoodisthatitcontainsamaterialthatisnotcellulose.Somethingcalledlignin.Thisisessentialforthetreesinceitholdsthecellulosefibrestogether,b
6、utifitisincorporatedintothemanufacturedpaperitpresentsarchivistswithaproblem.Lignineventuallybreaksdownandreleasesacidproductsintothepaper.Thiswillweakenthebondbetweenthecellulosefibersandthepaperwillbeebrittleandlookratherbrownandcareworn.Wehaveallseenthisinoldnewspapersandcheappaperbackbooks.Ithas
7、beenestimatedthatmostpaperbackbookswillhavealifeofnotgreaterthanfiftyyears.Notwhatweneedforourarchives. F)Sincethelignincanberemovedfromthepaperpulpduringmanufacture,theobviousquestioniswhyisitleftinthepaper?Theanswerliesinthefactthatligninmakesupaconsiderablepartofthetree.Byleavingthelignininthepul
8、papapermakercanincreasehispaperyieldfromatreetosome95%.Removingitmeansayieldofonly35%.Itisclearlyuneconomictoremovetheligninformanypaperandcardapplications. G)Italsomeans,ofcourse,thatligninfreepaperisgoingtobemoreexpensive,butthatisneverthelesswhatthearchivistmustlookforinhissupplies.Thereisnopoint
9、whatsoeverincarefullyplacingourvaluableartifactsinpaperorcardthatisgoingtohastentheirdemise.Acidisparticularlyharmfultophotographicmaterials,causingthemtofadeandissomecasessimplyvanish H)So,howdowetellapieceofsuitablepaperorcardfromonethatisunsuitable?Youcannotdoitbysimplylooking,andratherdisappoint
10、ingly,youcannotalwaysrelyonthelabel.Acidfreemightbetrueinasmuchasatestonthepapermayindicatethatitisaneutralmaterialatthistime.Butlignincantakeyearsbeforeitstartstheinevitableprocessofbreakingdown,andintherightconditionsitwillspeedupenormously. I)Addedtothis,asIhaveindicatedearlier,papermayalsocontai
11、nothermaterialsaddedduringmanufacturesuchasbleach,chinaclay,chemicalwhitenersandsize.Thislookslikeableakpicture,anditwouldbebutforthefactthattherearesupplierswhowillguaranteethematerialthattheysell.Ifyouwanttobeabsolutelysurethatyouarestoringin,orprintingon,thecorrectmaterialthenthisisprobablytheonl
12、yway. J)Incidentally,acidscanmigratefrommaterialtomaterial.Liningoldshoeboxeswithgoodqualityacidfreepaperwilldolittletoguardthecontents.Theacidwillgetthereintheend. PaperfromRag K)Paperisalsomonlymadefromcottonandragwaste.Thishastheadvantageofbeingligninfree,butbecausethereismuchlesscottonandragthan
13、trees,italsotendstobemuchmoreexpensivethanwoodpulppaper.Youwillstillneedtopurchasefromareliablesourcethough,sinceevenragpaperandcardcancontainundesirableadditives. L)Areliablesourceforqualityragpapersisarecognizedartstockiest.Manywatercolorartistsinsistonusingonlyfinequalityragpaperandboard. M)Thema
14、inlessontolearnfromthisinformationisthatyoucannotrelyonpurchasingarchivalmaterialsfromthehighstreet.Theonlysafesolutionistopurchasefromspecialistsuppliers.Itmaycostrathermore,butintheendyouwillknowthatyourimportantandvaluabledataandimageshavethebesthomepossible. 1.Thecornflakepacketischeaperthanhigh
15、gradecard. 2.Therearealotofmaterialswhichcanbeusedformakingpaper,butthesuperiorityonesaresoftwood,cottonandrags. 3.Duringthewholemanufacturingprocess,thefinalproductismadefromapulpofcellulosefibres. 4.Inordertomakewhitepaperandcard,themakerswilladdbleach. 5.Liguinisessentialforthetreebutitwillmakepa
16、pereasytobreak. 6.Manypaperproducerswillpreserveligninduringmanufacture,becauseleavingtheligninwillmakemorepaperfromatree. 7.Acidisparticularlyharmfultophotographicmaterials. 8.Iftheligninisremovedfromthepaper,thepaperwillbemoreexpensive. 9.Althoughfreeoflignin,papermadefromcottonandragwastecanalsocostmoremoneythanwo
