XX英语六级长篇阅读练习及答案解析

XXxx年大学即将到来，备考工作正在如火如荼地进展中，为了帮助大家更好的复习功课，以下是为大家搜索的xx长篇阅读练习及答案解析，希望能给大家带来帮助!更多精彩内容请及时关注我们!A)Wearesurroundedbysomuchpaperandcardthatitiseasytoforgetjusthowplexitis.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,therealityisrathermoreplicated.Inordertogiveusourwhitepaperandcard,themakerswilladdbleachandothermaterialssuchaschinaclayandadditionalchemicals.E)Afurtherproblemwithwoodisthatitcontainsamaterialthatisnotcellulose.Somethingcalledlignin.Thisisessentialforthetreesinceitholdsthecellulosefibrestogether,butifitisincorporatedintothemanufacturedpaperitpresentsarchivistswithaproblem.Lignineventuallybreaksdownandreleasesacidproductsintothepaper.Thiswillweakenthebondbetweenthecellulosefibersandthepaperwillbeebrittleandlookratherbrownandcareworn.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.PaperfromRagK)Paperisalsomonlymadefromcottonandragwaste.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.1.B根据题干中的信息提示词corn―flakepacket,highcard,可定位到文章第二段，该局部最后提到corn-flakepacket在制造过程中比高等级的纸(highgradecard)廉价.2.C根据题干中的信息提示