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1、ReadingREADINGPASSAGE1Youshouldspendabout20minutesonQuestions1-14whicharebasedonReadingPassage1onpages9and10.SpidersilkcutsweightofbridgesAstrong,lightbio-materialmadebygenesfromspiderscouldtransformconstructionandindustryAScientistshavesucceededincopyingthesilk-producinggenesofthe
2、GoldenOrbWeaverspiderandusingthemtocreateasyntheticmaterialwhichtheybelieveisthemodelforanewgenerationofadvancedbio-materials.Thenewmaterial,biosilk,whichhasbeenspunforthefirsttimebyresearchersatDuPont,hasanenormousrangeofpotentialusesinconstructionandmanufacturing.BTheattractionof
3、thesilkspunbythespiderisacombinationofgreatstrengthandenormouselasticity,whichman-madefibreshavebeenunabletoreplicate.Onanequal-weightbasis,spidersilkisfarstrongerthansteelanditisestimatedthatifasinglestrandcouldbemadeabout10mindiameter,itwouldbestrongenoughtostopajumbojetinflight.
4、Athirdimportantfactoristhatitisextremelylight.Armyscientistsarealreadylookingatthepossibilitiesofusingitforlightweight,bullet-proofvestsandparachutes.CForsometime,biochemistshavebeentryingtosynthesizethedrag-linesilkoftheGoldenOrbWeaver.Thedrag-linesilk,whichformstheradialarmsofthe
5、web,isstrongerthantheotherpartsofthewebandsomebiochemistsbelieveasyntheticversioncouldprovetobeasimportantamaterialasnylon,whichhasbeenaroundfor50years,sincethediscoveriesofWallaceCarothersandhisteamusheredintheageofpolymers.DTorecreatethematerial,scientists,includingRandolphLewisa
6、ttheUniversityofWyoming,firstexaminedthesilk-producingglandofthespider.“Wetookouttheglandsthatproducethesilkandlookedatthecodingfortheproteinmaterialtheymake,whichisspunintoaweb.WethenwentlookingforcloneswiththerightDNA,”hesays.EAtDuPont,researchershaveusedbothyeastandbacteriaashos
7、tstogrowtherawmaterial,whichtheyhavespunintofibres.RobertDorsch,Dupont’sdirectorofbiochemicaldevelopment,saystheglobulesofprotein,comparablewithmarblesinanegg,areharvestedandprocessed.“Webreakopenthebacteria,separateouttheglobulesofproteinandusethemastherowstartingmaterial.Withyeas
8、t,thegenesystemcanbedesign
