六级新题型段落阅读专项练习

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1、Paper—orethanMeetstheEyeA)Wearesur^roundedbysomuchpaperandcardtha/titiseasytcforgetjusthowcomp!exitis.Therearemanyvarietiesandgradesofpapermaterials,andwhilstitisfairlyeasytospotthevarieties，itisfarmoreclifficulttospotthegrades.B)丄tneedstobeuridorstoodthatrnostpaper*andcardismanufacturedforaspeci

2、ficpurpose,sotha/twhilstthecom—f*lakepacketmay1ooksmart,itisclearlynetsomethingdestinedfortheaarchives・JLtismacletolookgood,butonlyneedsalimitedlifespan・Itisalsomuchcheapertomanufacturethanhi曲gradoca±*d.C)Papercanbemadefromanalmostend!essv<±rietyofcel1ulose-basedma/terialwhichwi11includemanywoods

3、,cottonsandgrassesorwhichpapyrusisanexampleandfromwherewegettheword^paper^.Manyoftheseai'everyspecialized,buttheprepondo上ancoo£papermakinghasbeen£romso£twoodaridcottonorrags,withthebulkbeingwood—based.PaperfromWoodD)Inordertomakewoodintopaperitneedstobebrokenclownintofinestrands.Firstlybypowerful

4、machineryandthenboiledwithstrongalkaliossuchascausticsoda,unti1afinopulpofcellulosefibersisproduced.Ttisfromthispulpthatthefinalproductismade,relyingonthebondingtogetherof*thecel1uloseintolayers.That,inaverysmallnutshell,istheessenceofpapermakingfromwood.However,therealityisrathermorecomp1icated.

5、Inordertogiveusourwhitopaperandcard,themakerswilladdbleach<±nclctherma/terialssuchaschinaclayandadditionalchemicals.E)Afurtherproblemwithwoodisthatitcontainsamaterialthatisnotcellulose.Somethingcalledlignin.Thisisessentialforthetreesinceitho1dsthece1lulosoFibrestogether,butifitisincoY'poratedinto

6、themanufacturedpaperitpresentsarch1vistswithaproblem.Lignineventual1ybreaksdownandreleasesacidproductsintothepaper.Thiswillweakenthebondbetweenthecellulosefibersandthepaperwillbecomebrittleand1ookratherbrownandcareworn.Wohavea11seenthisinoldnewsp<±persandcheappaperbackbooks・Tthasbeenestimatedthat

7、mostpaperbackbookswi11haveallfeofnotgreaterthanfiftyyeaars・Notwha/tweneedforourarchives.F)Sincethelignincanboromovodfromthopapoi'pulpduringrnanufacturo,thoobviousquestionis"whyisit1eftinthop<±per?zzTheanswer1iesinthefa