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? ?阅读下面这篇短文，短文后有2项测试任务：(1)第23～26题要求从所给的6个选项中为第1～4段每段选择1个正确的小标题；(2)第27～30题要求从所给的6个选项中选择4个正确选项，分别完成每...
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? ?阅读下面这篇短文短文后有2项测试任务1第23～26题要求从所给的6个选项中为第1～4段每段选
? ?阅读下面这篇短文短文后有2项测试任务1第23～26题要求从所给的6个选项中为规定段每段选择1
? ?阅读下面这篇短文短文后有2项测试任务1第23～26题要求从所给的6个选项中为第1～4段每段选
? ?阅读下面这篇短文短文后有2项测试任务1第23～26题要求从所给的6个选项中为第1～4段每段选
? ?阅读下面这篇短文短文后有2项测试任务1第23～26题要求从所给的6个选项中为第2～5段每段选
? ?阅读下面这篇短文短文后有2项测试任务1第23～26题要求从所给的6个选项中为第2～5段每段选
? ?阅读下面这篇短文短文后有2项测试任务1第23～26题要求从所给的6个选项中为第2～5段每段选
? ?阅读下面这篇短文短文后有2项测试任务1第23～26题要求从所给的6个选项中为第1～4段每段选
? ?阅读下面这篇短文短文后有2项测试任务1第23～26题要求从所给的6个选项中为第1～4段每段选
? ?阅读下面这篇短文短文后有2项测试任务1第23～26题要求从所给的6个选项中为第1～4段每段选
? ?阅读下面这篇短文短文后有2项测试任务1第23～26题要求从所给的6个选项中为第2～5段每段选
? ?阅读下面这篇短文短文后有2项测试任务1第23～26题要求从所给的6个选项中为第1～4段每段选
? ?阅读下面这篇短文短文后有2项测试任务1第23～26题要求从所给的6个选项中为第2～5段每段选
? ?阅读下面这篇短文短文后有2项测试任务1第23～26题要求从所给的6个选项中为规定段每段选择1
? ?阅读下面这篇短文短文后有2项测试任务1第23～26题要求从所给的6个选项中为第2—5段每段选
? ?阅读下面这篇短文短文后有2项测试任务1第23～26题要求从所给的6个选项中为第2～5段每段选
? ?阅读下面这篇短文短文后有2项测试任务1第23～26题要求从所给的6个选项中为第1～4段每段选
? ?阅读下面这篇短文短文后有2项测试任务1第23～26题要求从所给的6个选项中为第2～5段每段选
? ?阅读下面这篇短文短文后有2项测试任务1第23～26题要求从所给的6个选项中为第1～4段每段选
? ?阅读下面这篇短文短文后有2项测试任务1第23～26题要求从所给的6个选项中为第2～5段每段选
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{{*HTML*}}下面的短文有5处空白短文后有6个句子其中5个取自短文请根据短文内容将其分别放回原有位置以恢复文章原貌 ? TheWorld’sLongestBridge? ?Rumorhasitthatalegendarysix-headedmonsterlurksinthedeepwaters oftheTyrhenianSeabetweenItalyandtheislandofSicily.{{U}}?46 ?{{/U}}Whencompletedin2010theworld’slongestbridgewillweightnearly 300000tons—equivalenttotheicebergthatsanktheTitanic—andstretch5 kilometerslong.That’snearly50percentlongerthananyotherbridgeever builtsaysstructuralengineerShaneRixon.??{{U}}?47 ?{{/U}}They’resuspensionbridgesmassivestructuresbuilttospanvast waterchannelsorgorges.Asuspensionbridgeneedsjusttwotowerstoshoulder thestructure’smammothweightthankstoheftysupportingcablesslungbetween thetowersandanchoredfirmlyindeeppoolsofcementateachendofthe bridge.TheMessinaStraitBridgewillhavetwo54100-tontowerswhichwill supportmostofthebridge’sload.Thebeefycablesofthebridgeeach1.2 meterindiameterwillholdupthelongestandwidestbridgedeckever built.??WhenconstructionbeginsontheMessinaStraitBridgein 2005thefirstjobwillbetoerecttwo370meter-tallsteeltowers. {{U}}?48?{{/U}}.Gettingthesecablesupwillbesomething.It’snot justtheirlength—totally5.3kilometers—buttheirweight.{{U}}?49 ?{{/U}}??Afterloweringverticalsuspendercablesfromthe maincablesbuilderswillerecta60meter-wide54630-tonsteelroadwayor deck—wideenoughtoaccommodate12lanesoftraffic.?Thedeck’sweight willpulldownonthecableswithaforceof70500tons.Inreturnthecables yankupagainsttheirfirmlyrootedanchorswithaforceof139000 tons—equivalenttotheweightofabout100000cars.Thoseanchorsare essential.{{U}}?50?{{/U}}??A.Someenvironmentalists areagainsttheprojectonbiologicalgrounds.??B.Whatdothe world’slongestbridgeshaveincommon???C.Iftrueonedayyou mightspythebeastwhilezipping呼啸而过acrosstheMessinaStrait Bridge.??D.They’rewhatwillkeepthebridgefromgoing anywhere.??E.Thesecondjobwillbetopulltwosetsofsteel cablesacrossthestraiteachsetbeingabundleof44352individualsteel wires.??F.Theywilltipupthescalesat166500tons—morethan halfthebridge’stotalmass.
AmericansDecrease IncreasinglyhistoriansareblamingdiseasesimportedfromtheOldWorldforthestaggeringdisparity不同betweentheindigenous本土的populationofAmericain1492—newestimatesofwhichsoarashighas100millionorapproximatelyone-sixthofthehumanraceatthattime—andthefewmillionfull-bloodedNativeAmericansaliveattheendofthenineteenthcentury.Thereisnodoubtthatchronicdiseasewasanimportantfactorintheprecipitous险峻的declineanditishighlyprobablethatthegreatestkillerwasepidemicdiseaseespeciallyasmanifestedinvirgin-soil处女地epidemics. Virgin-soilepidemicsarethoseinwhichthepopulationsatriskhavehadnopreviouscontactwiththediseasesthatstrikethemandarethereforeimmunologically免疫学的almostdefenseless.Thatvirgin-soilepidemicswereimportantinAmericanhistoryisstronglyindicatedbyevidencethatanumberofdangerousmaladies病—smallpoxmeasles麻疹malaria疟病yellowfeverandundoubtedlyseveralmore—wereunknowninthepre-ColumbianNewWorld.TheeffectsoftheirsuddenintroductionaredemonstratedintheearlychroniclesofAmericawhichcontainreportsofhorrendous可怕的epidemicsandsteeppopulationdeclinesconfirmedinmanycasesbyrecentequantitativeanalysesofSpanishtributerecordsandothersources.TheevidenceprovidedbythedocumentsofBritishandFrenchcoloniesisnotasdefinitivebecausetheconquerorsofthoseareasdidnotestablishpermanentsettlementsandbegintokeepcontinuousrecordsuntiltheseventiethcenturybywhichtimetheworstepidemicshadprobablyalreadytakenplace.FurthermoretheBritishtendedtodrivethenativepopulationsawayratherthanenslavingthemastheSpaniardsdidsothattheepidemicsofBritishAmericaoccurredbeyondtherangeofcolonistsdirectobservation. EvensothesurvivingrecordsofNorthAmericadocontainreferencestodeadlyepidemicsamongtheindigenouspopulation.In1616—1619anepidemicpossiblyofbubonicorpneumonic肺的plague瘟疫sweptcoastalNewEnglandkillingasmanyasnineoutoften.Duringthe1630’’ssmall-poxthediseasemostfataltotheNativeAmericanpeopleeliminatedhalfthepopulationoftheHuronandIroquoisconfederations.Inthe1820’’sfeverdevastatedthepeopleoftheCoulumbiaRiverareakillingeightoutoftenofthem. UnfortunatelythedocumentationoftheseandotherepidemicsisslightandfrequentlyunreliableanditisnecessarytosupplementwhatlittlewedoknowwithevidencefromrecentepidemicsamongNativeAmericans.Forexamplein1952anoutbreakofmeaslesamongtheNativeAmericaninhabitantsofUngavaBay.Quebecaffected99percentofthepopulationandkilled7percenteventhoughsomehadthebenefitofmodernmedicine.Casessuchasthisdemonstratethatevendiseasesthatarenotnormallyfatalcanhavedevastatingconsequenceswhentheystrikeanimmunologicallydefenselesscommunity. WhichofthefollowingcanbeinferredfromthepassageabouttheNativeAmericaninhabitantsofUngavaBay?
OnAntibodies Substancesforeigntothebodysuchasdisease-causingbacteriaandvirusesandotherinfectiousagentsarerecognizedbythebodysimmunesystemasinvaders.Ournaturaldefensesagainsttheseinfectiousagentsareantibodiesproteinsthatseekouttheantigens抗原andhelpdestroythem. Antibodieshavetwoveryusefulcharacteristics.Firsttheyareextremelyspecific;thatiseachantibodybindstoandattacksoneparticularantigen.Secondsomeantibodiesonceactivatedbytheoccurrenceofadiseasecontinuetoconferresistanceagainstthatdisease.Classicexamplearetheantibodiestothechildhooddiseasesofchickenpox水痘andmeasles. Thesecondcharacteristicofantibodiesmakesitpossibletodevelopvaccines.Avaccine痘苗isapreparationofkilledorweakenedbacteriaorvirusesthatwhenintroducedintothebodystimulatestheproductionofantibodiesagainsttheantigensitcontains. Itisthefirsttraitofantibodiestheirspecificitythatmakesmonoclonalantibodytechnologysovaluable.Notonlycanantibodiesbeusedtherapeutically在治疗上toprotectagainstdisease;theycanalsohelpto.diagnoseawidevarietyofillnessesandcandetectthepresenceofdrugsviralandbacterialproductsandotherunusualorabnormalsubstancesintheblood. Givensuchadiversityofusesforthesediseased-fightingsubstancestheirproductioninpurequantitieshaslongbeenthefocusofscientificinvestigation.Theconventionalmethodwastoinjectalaboratoryanimalwithanantigenandthenafterantibodieshadbeenformedcollectthoseantibodiesfromthebloodserum血清Antibodycontainingbloodserumiscalledantiserum抗血清.Therearetwoproblemswiththismethod:Ityieldsantiserumthatcontainsundesiredsubstancesanditprovidesaverysmallamountofusableantibody. Monoclonalantibodytechnologyallowsustoproducelargeamountsofpureantibodies.inthefollowingway:wecanobtaincellsthatproduceantibodiesnaturally;wealsohaveavailableaclassofcellsthatcangrowcontinuallyincellculture培养.Ifweformahybrid混血儿thatcombinesthecharacteristicofimmortality永生withtheabilitytoproducethedesiredsubstancewewouldhaveineffectafactorytoproduceantibodiesthatworkaroundtheclock. Inmonoclonalantibodytechnologytumorcellsthatcanreplicate重复endlesslyarefusedwithmammaliancellsthatproduceanantibody.Theresultofthiscellfusionisahybridoma杂交瘤whichwillcontinuallyproduceantibodies.Theseantibodiesarecalledmonoclonalbecausetheycomefromonlyonetypeofcellthehybridomacell;antibodiesproducedbyconventionalmethodsontheotherhandarederivedfrompreparationscontainingmanykindsofcellsandhencearecalledpolyclonal.Anexampleofhowmonoclonalantibodiesarederivedisdescribedbelow. Amyelomaisatumorofthebonemarrow骨髓thatcanbeadaptedtogrowpermanendyincellculture.Whenmyelomacellswerefusedwithantibody-producingmammalianspleencellsitwasfoundthattheresultinghybridcellsorhybridomasproducedlargeamountsofmonoclonal骨髓瘤antibody.Thisproductofcellfusioncombinedthedesiredqualitiesofthetwodifferenttypesofcells:theabilitytogrowcontinuallyandtheabilitytoproducelargeamountsofpureantibody. Becauseselectedhybridcellsproduceonlyonespecificantibodytheyaremorepurethanthepolyclonalantibodiesproducedbyconventionaltechniques.Theyarepotentiallymoreeffectivethanconventionaldrugsinfightingdiseasesincedrugsattacknotonlytheforeignsubstancebutthebody’sowncellsaswellsometimesproducingundesirablesideeffectssuchasnausea恶心andallergicreactions.Monoclonalantibodiesattackthetargetmoleculeandonlythetargetmoleculewithnoorgreatlydiminishedsideeffects. Allthefollowingstatementsaboutantibodiesaretrueexcept______.
CigarsInstead? Smokingoneortwocigarsadaydoublestheriskofcancersoftheliptonguemouthandthroataccordingtoagovernmentstudy. DailycigarsalsoincreasetheriskoflungcancerandcanceroftheesophagusandincreasetheriskofcancerofthelarynxvoiceboxsixfoldsayresearchersattheNationalCancerInstituteinBethesdaMaryland. Inadditionthereportrevealedthatsmokingthreeorfourcigarsadayincreasedtheriskoforalcancerto8.5timestheriskfornonsmokersandtheriskofesophagealcancerbyfourtimestheriskofnonsmokers. ThehealtheffectsofsmokingcigarsisoneofeightsectionsofthearticleCigars:HealthEffectsandTrends.Theresearchersreportthatcomparedwithacigarettealargecigaremitsupto90timesasmuchcarcinogenictobacco-specificnitrosamines ThisarticleprovidesclearandinvaluableinformationaboutthedisturbingincreaseincigaruseandthesignificantpublichealthconsequencesforthecountrysaidDr.RichardKlausnerdirectoroftheNationalCancerInstituteinastatement. Thedataareclear-theharmfulsubstancesandcarcinogensincigarsmokelikecigarettesareassociatedwiththeincreasedrisksofseveralkindsofcancersaswellasheartandlungdiseasesheadded.Inotherwordscigarsarenotsafealternativestocigarettesandmaybeaddictive. Tothoseindividualswhomaybethinkingaboutsmokingcigarsouradvicesis—don’’t.TothosecurrentlysmokingcigarsquittingistheonlywaytoeliminatecompletelythecancerheartandlungdiseaseriskswarnedKlausner. AccordingtoaNationalCancerInstitutepressreleasetherehaven’’tbeenanystudiesonthehealtheffectsonnonsmokersatcigarsocialeventsbut...asignificantbodyofevidenceclearlydemonstratesanincreasedlungcancerriskfromsecondhandsmoke. Inthepassagehowmanycancersarementionedinrelationtosmokingcigarsdaily?
Thetraincametoanabruptstopmakinguswonderwherewewere.
Dyslexia Asmanyas20%ofallchildrenintheUnitedStatessufferfromsomeformofthelearningdisorder2calleddyslexia. Expertsondyslexiasaythattheproblemisnotadisease.Theysaythatpersonswithdyslexiauseinformationinadifferentway.Oneoftheworldsgreatthinkersandscientists.AlbertEinsteinwasdyslexic.Einsteinsaidthatheneverthoughtinwordsthewaythatmostpeopledo.Hesaidthathethoughtinpicturesinstead. TheAmericaninventorThomasEdisonwasalsodyslexic.DyslexiafirstwasrecognizedinEuropeandtheUnitedStatesmorethan80yearsago.Manyyearspassedbeforedoctorsdiscoveredthatpersonswiththedisorderwerenotmentallyslowordisabled.Thedoctorsfoundthatthebrainsofpersonswithdyslexiaaredifferent. Inmostpeopletheleftsideofthebrain—thepartthatcontrolslanguageislargerthantherightside.Inpersonswithdyslexiatherightsideofthebrainisbigger.Doctorsarenotsurewhatcausesthisdifference.Howeverresearchhasshownthatdyslexiaismorecommoninmalesthaninfemalesanditisfoundmoreofteninpersonswhoarelefthanded4.Nooneknowsthecauseofdyslexiabutsomescientistsbelievethatitmayresultfromchemicalchangesinababy’’sbodylongbeforeitisborn.Theyaretryingtofindwaystoteachpersonswithdyslexia.Dyslexicpersonsthinkdifferentlyandneedspecialkindsofteachinghelp.Aftertheyhavesolvedtheirproblemswithlanguagetheyoftenshowthemselvestobeespeciallyintelligentorcreative. ThefirstcasesofdyslexiainEuropewerediscoveredlessthanacenturyago.
{{*HTML*}}下面的短文有15处空白请根据短文内容为每处空白确定1个最佳选项 ?? WonderWebs??Spiderwebs aremorethanhomesandtheyareingenioustraps.Andtheworld’sbestweb spinnermaybetheGoldernOrbWeaverspider.ThefemaleOrbWeaverspinsaweb offibersthinenoughtobeinvisibletoinsect?yet{{U}}?51 ?{{/U}}enoughtosnareaflyingbirdwithoutbreaking.??The secretoftheweb’sstrength.Atypeofsuper-resilient{{U}}?52?{{/U}} calleddragline.Whenthefemalespiderisreadyto{{U}}?53?{{/U}}the web’sspokesandframesheusesherlegstodrawtheairythreadoutthrougha hollownozzleinherbelly.Draglineisnotstickysothespidercanraceback andforthalong{{U}}?54?{{/U}}tospintheweb’strademark spiral.??Unlikesomespidersthatweaveanewwebeverydaya GoldenOrbWeaver{{U}}?55?{{/U}}herhandiworkuntilitfailsapart sometimesnotfortwoyears.Thesilkythreadisfivetimesstrongerthansteel byweightandabsorbstheforceofanimpactthreetimesbetterthanKevlara highstrengthhuman-made{{U}}?56?{{/U}}usedinbullet-proofvests. ?Andthankstoitshightensilestrengthortheabilitytoresistbreaking underthepullingforcecalledtensionasinglestrandcanstretchupto40 percentlongerthanitsoriginal{{U}}?57?{{/U}}andsnapbackaswell asnew.Nohuman-madefiberevencomes{{U}}?58?{{/U}}.? ?Itisno{{U}}?59?{{/U}}manufacturersareclamoringforspider silk.Intheconsumerpipeline:high-performancefabricsforathletesand stockingsthatneverrun.Thinkparachutecordsandsuspensionbridgecables.A steady{{U}}?60?{{/U}}ofspidersilkwouldbeworthbillionsof dollars—buthowtoproduceit?Harvestingsilkonspiderfarmsdoesnot {{U}}?61?{{/U}}becausetheterritorialarthropodshaveatendencyto devourtheirneighbors.??Nowscientistsatthebiotechnology companyNexiaarespinningartificialsilkmodeledafterGoldernOrbdragline. The{{U}}?62?{{/U}}step:extractsilk-makinggenesfromthespiders. Nextimplantthegenesintogoateggcells.Thenannygoatsthatgrowfromthe eggssecretedraglinesilkproteinsintheir{{U}}?63?{{/U}}.The younggoatspassonthesilk-makinggenewithout{{U}}?64?{{/U}}help fromussaysNexiapresidentJeffreyTurner.?Nexiaisstillperfecting thespinningprocessbuttheyhopeartificialspidersilkwillsoonbesnagging customers{{U}}?65?{{/U}}therealthingsnags bugs.
Dyslexia Asmanyas20%ofallchildrenintheUnitedStatessufferfromsomeformofthelearningdisorder2calleddyslexia. Expertsondyslexiasaythattheproblemisnotadisease.Theysaythatpersonswithdyslexiauseinformationinadifferentway.Oneoftheworldsgreatthinkersandscientists.AlbertEinsteinwasdyslexic.Einsteinsaidthatheneverthoughtinwordsthewaythatmostpeopledo.Hesaidthathethoughtinpicturesinstead. TheAmericaninventorThomasEdisonwasalsodyslexic.DyslexiafirstwasrecognizedinEuropeandtheUnitedStatesmorethan80yearsago.Manyyearspassedbeforedoctorsdiscoveredthatpersonswiththedisorderwerenotmentallyslowordisabled.Thedoctorsfoundthatthebrainsofpersonswithdyslexiaaredifferent. Inmostpeopletheleftsideofthebrain—thepartthatcontrolslanguageislargerthantherightside.Inpersonswithdyslexiatherightsideofthebrainisbigger.Doctorsarenotsurewhatcausesthisdifference.Howeverresearchhasshownthatdyslexiaismorecommoninmalesthaninfemalesanditisfoundmoreofteninpersonswhoarelefthanded4.Nooneknowsthecauseofdyslexiabutsomescientistsbelievethatitmayresultfromchemicalchangesinababy’’sbodylongbeforeitisborn.Theyaretryingtofindwaystoteachpersonswithdyslexia.Dyslexicpersonsthinkdifferentlyandneedspecialkindsofteachinghelp.Aftertheyhavesolvedtheirproblemswithlanguagetheyoftenshowthemselvestobeespeciallyintelligentorcreative. Dyslexicpeopleoftenturnouttobeintelligentorcreativeonetheyhavelearnedtohandlelanguageproperly.
Thegovernmentwouldnotdaretoimposetaxesonsuchnecessitiesasbreadormilk.
Language Whenmostofusthinkaboutlanguagewethinkfirstaboutwords.Thusthehardestpartoflearningaforeignlanguagemayseemtobememorizing【51】vocabulary;whenweobserveachildfirstacquiringspeechwetalkofhisprogress【52】amatteroflearningnewwords.Wearealso【53】tofeelthattheadultspeakerwiththelargestvocabularyhasthebest【54】ofEnglish.Tothink【55】alanguageasjustastockofwordsis【56】quitewrong.Wordsalonedonot【57】alanguage;agrammaris【58】tocombinetheminsomeintelligibleway.Moreoverwordsarerelativelyeasytolearnandindeedallofusgo【59】learningthemallour【60】.Theyarealsothe【61】stablepartoflanguage.Wordscomeinto【62】changetheirpronunciationsandmeaningsanddisappearcompletelyallwithcomparativeease.Yetitistruethatthe【63】isfocusoflanguage.Itisinwords【64】soundsandmeaningsinterlocktoallowusto【65】withoneanotheranditiswordsthatwearrangetogethertomakesentencesconversationsanddiscourseofallkinds.Thuswehaveaparadoxinthatthemostshort-livedpartoflanguageisalsothecentrewheremeaningpronunciationandgrammarcometogether.
{{*HTML*}}下面的短文有15处空白请根据短文内容为每处空白确定1个最佳选项 ?? WonderWebs??Spiderwebs aremorethanhomesandtheyareingenioustraps.Andtheworld’sbestweb spinnermaybetheGoldernOrbWeaverspider.ThefemaleOrbWeaverspinsaweb offibersthinenoughtobeinvisibletoinsect?yet{{U}}?51 ?{{/U}}enoughtosnareaflyingbirdwithoutbreaking.??The secretoftheweb’sstrength.Atypeofsuper-resilient{{U}}?52?{{/U}} calleddragline.Whenthefemalespiderisreadyto{{U}}?53?{{/U}}the web’sspokesandframesheusesherlegstodrawtheairythreadoutthrougha hollownozzleinherbelly.Draglineisnotstickysothespidercanraceback andforthalong{{U}}?54?{{/U}}tospintheweb’strademark spiral.??Unlikesomespidersthatweaveanewwebeverydaya GoldenOrbWeaver{{U}}?55?{{/U}}herhandiworkuntilitfailsapart sometimesnotfortwoyears.Thesilkythreadisfivetimesstrongerthansteel byweightandabsorbstheforceofanimpactthreetimesbetterthanKevlara highstrengthhuman-made{{U}}?56?{{/U}}usedinbullet-proofvests. ?Andthankstoitshightensilestrengthortheabilitytoresistbreaking underthepullingforcecalledtensionasinglestrandcanstretchupto40 percentlongerthanitsoriginal{{U}}?57?{{/U}}andsnapbackaswell asnew.Nohuman-madefiberevencomes{{U}}?58?{{/U}}.? ?Itisno{{U}}?59?{{/U}}manufacturersareclamoringforspider silk.Intheconsumerpipeline:high-performancefabricsforathletesand stockingsthatneverrun.Thinkparachutecordsandsuspensionbridgecables.A steady{{U}}?60?{{/U}}ofspidersilkwouldbeworthbillionsof dollars—buthowtoproduceit?Harvestingsilkonspiderfarmsdoesnot {{U}}?61?{{/U}}becausetheterritorialarthropodshaveatendencyto devourtheirneighbors.??Nowscientistsatthebiotechnology companyNexiaarespinningartificialsilkmodeledafterGoldernOrbdragline. The{{U}}?62?{{/U}}step:extractsilk-makinggenesfromthespiders. Nextimplantthegenesintogoateggcells.Thenannygoatsthatgrowfromthe eggssecretedraglinesilkproteinsintheir{{U}}?63?{{/U}}.The younggoatspassonthesilk-makinggenewithout{{U}}?64?{{/U}}help fromussaysNexiapresidentJeffreyTurner.?Nexiaisstillperfecting thespinningprocessbuttheyhopeartificialspidersilkwillsoonbesnagging customers{{U}}?65?{{/U}}therealthingsnags bugs.
{{*HTML*}}下面的短文有15处空白请根据短文内容为每处空白确定1个最佳选项 ?? WonderWebs??Spiderwebs aremorethanhomesandtheyareingenioustraps.Andtheworld’sbestweb spinnermaybetheGoldernOrbWeaverspider.ThefemaleOrbWeaverspinsaweb offibersthinenoughtobeinvisibletoinsect?yet{{U}}?51 ?{{/U}}enoughtosnareaflyingbirdwithoutbreaking.??The secretoftheweb’sstrength.Atypeofsuper-resilient{{U}}?52?{{/U}} calleddragline.Whenthefemalespiderisreadyto{{U}}?53?{{/U}}the web’sspokesandframesheusesherlegstodrawtheairythreadoutthrougha hollownozzleinherbelly.Draglineisnotstickysothespidercanraceback andforthalong{{U}}?54?{{/U}}tospintheweb’strademark spiral.??Unlikesomespidersthatweaveanewwebeverydaya GoldenOrbWeaver{{U}}?55?{{/U}}herhandiworkuntilitfailsapart sometimesnotfortwoyears.Thesilkythreadisfivetimesstrongerthansteel byweightandabsorbstheforceofanimpactthreetimesbetterthanKevlara highstrengthhuman-made{{U}}?56?{{/U}}usedinbullet-proofvests. ?Andthankstoitshightensilestrengthortheabilitytoresistbreaking underthepullingforcecalledtensionasinglestrandcanstretchupto40 percentlongerthanitsoriginal{{U}}?57?{{/U}}andsnapbackaswell asnew.Nohuman-madefiberevencomes{{U}}?58?{{/U}}.? ?Itisno{{U}}?59?{{/U}}manufacturersareclamoringforspider silk.Intheconsumerpipeline:high-performancefabricsforathletesand stockingsthatneverrun.Thinkparachutecordsandsuspensionbridgecables.A steady{{U}}?60?{{/U}}ofspidersilkwouldbeworthbillionsof dollars—buthowtoproduceit?Harvestingsilkonspiderfarmsdoesnot {{U}}?61?{{/U}}becausetheterritorialarthropodshaveatendencyto devourtheirneighbors.??Nowscientistsatthebiotechnology companyNexiaarespinningartificialsilkmodeledafterGoldernOrbdragline. The{{U}}?62?{{/U}}step:extractsilk-makinggenesfromthespiders. Nextimplantthegenesintogoateggcells.Thenannygoatsthatgrowfromthe eggssecretedraglinesilkproteinsintheir{{U}}?63?{{/U}}.The younggoatspassonthesilk-makinggenewithout{{U}}?64?{{/U}}help fromussaysNexiapresidentJeffreyTurner.?Nexiaisstillperfecting thespinningprocessbuttheyhopeartificialspidersilkwillsoonbesnagging customers{{U}}?65?{{/U}}therealthingsnags bugs.
{{*HTML*}}下面的短文有15处空白请根据短文内容为每处空白确定1个最佳选项 ?? WonderWebs??Spiderwebs aremorethanhomesandtheyareingenioustraps.Andtheworld’sbestweb spinnermaybetheGoldernOrbWeaverspider.ThefemaleOrbWeaverspinsaweb offibersthinenoughtobeinvisibletoinsect?yet{{U}}?51 ?{{/U}}enoughtosnareaflyingbirdwithoutbreaking.??The secretoftheweb’sstrength.Atypeofsuper-resilient{{U}}?52?{{/U}} calleddragline.Whenthefemalespiderisreadyto{{U}}?53?{{/U}}the web’sspokesandframesheusesherlegstodrawtheairythreadoutthrougha hollownozzleinherbelly.Draglineisnotstickysothespidercanraceback andforthalong{{U}}?54?{{/U}}tospintheweb’strademark spiral.??Unlikesomespidersthatweaveanewwebeverydaya GoldenOrbWeaver{{U}}?55?{{/U}}herhandiworkuntilitfailsapart sometimesnotfortwoyears.Thesilkythreadisfivetimesstrongerthansteel byweightandabsorbstheforceofanimpactthreetimesbetterthanKevlara highstrengthhuman-made{{U}}?56?{{/U}}usedinbullet-proofvests. ?Andthankstoitshightensilestrengthortheabilitytoresistbreaking underthepullingforcecalledtensionasinglestrandcanstretchupto40 percentlongerthanitsoriginal{{U}}?57?{{/U}}andsnapbackaswell asnew.Nohuman-madefiberevencomes{{U}}?58?{{/U}}.? ?Itisno{{U}}?59?{{/U}}manufacturersareclamoringforspider silk.Intheconsumerpipeline:high-performancefabricsforathletesand stockingsthatneverrun.Thinkparachutecordsandsuspensionbridgecables.A steady{{U}}?60?{{/U}}ofspidersilkwouldbeworthbillionsof dollars—buthowtoproduceit?Harvestingsilkonspiderfarmsdoesnot {{U}}?61?{{/U}}becausetheterritorialarthropodshaveatendencyto devourtheirneighbors.??Nowscientistsatthebiotechnology companyNexiaarespinningartificialsilkmodeledafterGoldernOrbdragline. The{{U}}?62?{{/U}}step:extractsilk-makinggenesfromthespiders. Nextimplantthegenesintogoateggcells.Thenannygoatsthatgrowfromthe eggssecretedraglinesilkproteinsintheir{{U}}?63?{{/U}}.The younggoatspassonthesilk-makinggenewithout{{U}}?64?{{/U}}help fromussaysNexiapresidentJeffreyTurner.?Nexiaisstillperfecting thespinningprocessbuttheyhopeartificialspidersilkwillsoonbesnagging customers{{U}}?65?{{/U}}therealthingsnags bugs.
Theyjoinedthearmywillingly.
{{*HTML*}}下面的短文有15处空白请根据短文内容为每处空白确定1个最佳选项 ?? WonderWebs??Spiderwebs aremorethanhomesandtheyareingenioustraps.Andtheworld’sbestweb spinnermaybetheGoldernOrbWeaverspider.ThefemaleOrbWeaverspinsaweb offibersthinenoughtobeinvisibletoinsect?yet{{U}}?51 ?{{/U}}enoughtosnareaflyingbirdwithoutbreaking.??The secretoftheweb’sstrength.Atypeofsuper-resilient{{U}}?52?{{/U}} calleddragline.Whenthefemalespiderisreadyto{{U}}?53?{{/U}}the web’sspokesandframesheusesherlegstodrawtheairythreadoutthrougha hollownozzleinherbelly.Draglineisnotstickysothespidercanraceback andforthalong{{U}}?54?{{/U}}tospintheweb’strademark spiral.??Unlikesomespidersthatweaveanewwebeverydaya GoldenOrbWeaver{{U}}?55?{{/U}}herhandiworkuntilitfailsapart sometimesnotfortwoyears.Thesilkythreadisfivetimesstrongerthansteel byweightandabsorbstheforceofanimpactthreetimesbetterthanKevlara highstrengthhuman-made{{U}}?56?{{/U}}usedinbullet-proofvests. ?Andthankstoitshightensilestrengthortheabilitytoresistbreaking underthepullingforcecalledtensionasinglestrandcanstretchupto40 percentlongerthanitsoriginal{{U}}?57?{{/U}}andsnapbackaswell asnew.Nohuman-madefiberevencomes{{U}}?58?{{/U}}.? ?Itisno{{U}}?59?{{/U}}manufacturersareclamoringforspider silk.Intheconsumerpipeline:high-performancefabricsforathletesand stockingsthatneverrun.Thinkparachutecordsandsuspensionbridgecables.A steady{{U}}?60?{{/U}}ofspidersilkwouldbeworthbillionsof dollars—buthowtoproduceit?Harvestingsilkonspiderfarmsdoesnot {{U}}?61?{{/U}}becausetheterritorialarthropodshaveatendencyto devourtheirneighbors.??Nowscientistsatthebiotechnology companyNexiaarespinningartificialsilkmodeledafterGoldernOrbdragline. The{{U}}?62?{{/U}}step:extractsilk-makinggenesfromthespiders. Nextimplantthegenesintogoateggcells.Thenannygoatsthatgrowfromthe eggssecretedraglinesilkproteinsintheir{{U}}?63?{{/U}}.The younggoatspassonthesilk-makinggenewithout{{U}}?64?{{/U}}help fromussaysNexiapresidentJeffreyTurner.?Nexiaisstillperfecting thespinningprocessbuttheyhopeartificialspidersilkwillsoonbesnagging customers{{U}}?65?{{/U}}therealthingsnags bugs.
Language Whenmostofusthinkaboutlanguagewethinkfirstaboutwords.Thusthehardestpartoflearningaforeignlanguagemayseemtobememorizing【51】vocabulary;whenweobserveachildfirstacquiringspeechwetalkofhisprogress【52】amatteroflearningnewwords.Wearealso【53】tofeelthattheadultspeakerwiththelargestvocabularyhasthebest【54】ofEnglish.Tothink【55】alanguageasjustastockofwordsis【56】quitewrong.Wordsalonedonot【57】alanguage;agrammaris【58】tocombinetheminsomeintelligibleway.Moreoverwordsarerelativelyeasytolearnandindeedallofusgo【59】learningthemallour【60】.Theyarealsothe【61】stablepartoflanguage.Wordscomeinto【62】changetheirpronunciationsandmeaningsanddisappearcompletelyallwithcomparativeease.Yetitistruethatthe【63】isfocusoflanguage.Itisinwords【64】soundsandmeaningsinterlocktoallowusto【65】withoneanotheranditiswordsthatwearrangetogethertomakesentencesconversationsanddiscourseofallkinds.Thuswehaveaparadoxinthatthemostshort-livedpartoflanguageisalsothecentrewheremeaningpronunciationandgrammarcometogether.
Hetookustoanautomobileshowyesterdayafternoon.
Hisplanshouldsucceedforitseemsquitefeasible.
{{*HTML*}}下面的短文有15处空白请根据短文内容为每处空白确定1个最佳选项 ?? WonderWebs??Spiderwebs aremorethanhomesandtheyareingenioustraps.Andtheworld’sbestweb spinnermaybetheGoldernOrbWeaverspider.ThefemaleOrbWeaverspinsaweb offibersthinenoughtobeinvisibletoinsect?yet{{U}}?51 ?{{/U}}enoughtosnareaflyingbirdwithoutbreaking.??The secretoftheweb’sstrength.Atypeofsuper-resilient{{U}}?52?{{/U}} calleddragline.Whenthefemalespiderisreadyto{{U}}?53?{{/U}}the web’sspokesandframesheusesherlegstodrawtheairythreadoutthrougha hollownozzleinherbelly.Draglineisnotstickysothespidercanraceback andforthalong{{U}}?54?{{/U}}tospintheweb’strademark spiral.??Unlikesomespidersthatweaveanewwebeverydaya GoldenOrbWeaver{{U}}?55?{{/U}}herhandiworkuntilitfailsapart sometimesnotfortwoyears.Thesilkythreadisfivetimesstrongerthansteel byweightandabsorbstheforceofanimpactthreetimesbetterthanKevlara highstrengthhuman-made{{U}}?56?{{/U}}usedinbullet-proofvests. ?Andthankstoitshightensilestrengthortheabilitytoresistbreaking underthepullingforcecalledtensionasinglestrandcanstretchupto40 percentlongerthanitsoriginal{{U}}?57?{{/U}}andsnapbackaswell asnew.Nohuman-madefiberevencomes{{U}}?58?{{/U}}.? ?Itisno{{U}}?59?{{/U}}manufacturersareclamoringforspider silk.Intheconsumerpipeline:high-performancefabricsforathletesand stockingsthatneverrun.Thinkparachutecordsandsuspensionbridgecables.A steady{{U}}?60?{{/U}}ofspidersilkwouldbeworthbillionsof dollars—buthowtoproduceit?Harvestingsilkonspiderfarmsdoesnot {{U}}?61?{{/U}}becausetheterritorialarthropodshaveatendencyto devourtheirneighbors.??Nowscientistsatthebiotechnology companyNexiaarespinningartificialsilkmodeledafterGoldernOrbdragline. The{{U}}?62?{{/U}}step:extractsilk-makinggenesfromthespiders. Nextimplantthegenesintogoateggcells.Thenannygoatsthatgrowfromthe eggssecretedraglinesilkproteinsintheir{{U}}?63?{{/U}}.The younggoatspassonthesilk-makinggenewithout{{U}}?64?{{/U}}help fromussaysNexiapresidentJeffreyTurner.?Nexiaisstillperfecting thespinningprocessbuttheyhopeartificialspidersilkwillsoonbesnagging customers{{U}}?65?{{/U}}therealthingsnags bugs.
Dyslexia Asmanyas20%ofallchildrenintheUnitedStatessufferfromsomeformofthelearningdisorder2calleddyslexia. Expertsondyslexiasaythattheproblemisnotadisease.Theysaythatpersonswithdyslexiauseinformationinadifferentway.Oneoftheworldsgreatthinkersandscientists.AlbertEinsteinwasdyslexic.Einsteinsaidthatheneverthoughtinwordsthewaythatmostpeopledo.Hesaidthathethoughtinpicturesinstead. TheAmericaninventorThomasEdisonwasalsodyslexic.DyslexiafirstwasrecognizedinEuropeandtheUnitedStatesmorethan80yearsago.Manyyearspassedbeforedoctorsdiscoveredthatpersonswiththedisorderwerenotmentallyslowordisabled.Thedoctorsfoundthatthebrainsofpersonswithdyslexiaaredifferent. Inmostpeopletheleftsideofthebrain—thepartthatcontrolslanguageislargerthantherightside.Inpersonswithdyslexiatherightsideofthebrainisbigger.Doctorsarenotsurewhatcausesthisdifference.Howeverresearchhasshownthatdyslexiaismorecommoninmalesthaninfemalesanditisfoundmoreofteninpersonswhoarelefthanded4.Nooneknowsthecauseofdyslexiabutsomescientistsbelievethatitmayresultfromchemicalchangesinababy’’sbodylongbeforeitisborn.Theyaretryingtofindwaystoteachpersonswithdyslexia.Dyslexicpersonsthinkdifferentlyandneedspecialkindsofteachinghelp.Aftertheyhavesolvedtheirproblemswithlanguagetheyoftenshowthemselvestobeespeciallyintelligentorcreative. OneoutoffiveAmericanchildrensuffersfromdyslexia.
{{*HTML*}}下面的短文有15处空白请根据短文内容为每处空白确定1个最佳选项 ?? WonderWebs??Spiderwebs aremorethanhomesandtheyareingenioustraps.Andtheworld’sbestweb spinnermaybetheGoldernOrbWeaverspider.ThefemaleOrbWeaverspinsaweb offibersthinenoughtobeinvisibletoinsect?yet{{U}}?51 ?{{/U}}enoughtosnareaflyingbirdwithoutbreaking.??The secretoftheweb’sstrength.Atypeofsuper-resilient{{U}}?52?{{/U}} calleddragline.Whenthefemalespiderisreadyto{{U}}?53?{{/U}}the web’sspokesandframesheusesherlegstodrawtheairythreadoutthrougha hollownozzleinherbelly.Draglineisnotstickysothespidercanraceback andforthalong{{U}}?54?{{/U}}tospintheweb’strademark spiral.??Unlikesomespidersthatweaveanewwebeverydaya GoldenOrbWeaver{{U}}?55?{{/U}}herhandiworkuntilitfailsapart sometimesnotfortwoyears.Thesilkythreadisfivetimesstrongerthansteel byweightandabsorbstheforceofanimpactthreetimesbetterthanKevlara highstrengthhuman-made{{U}}?56?{{/U}}usedinbullet-proofvests. ?Andthankstoitshightensilestrengthortheabilitytoresistbreaking underthepullingforcecalledtensionasinglestrandcanstretchupto40 percentlongerthanitsoriginal{{U}}?57?{{/U}}andsnapbackaswell asnew.Nohuman-madefiberevencomes{{U}}?58?{{/U}}.? ?Itisno{{U}}?59?{{/U}}manufacturersareclamoringforspider silk.Intheconsumerpipeline:high-performancefabricsforathletesand stockingsthatneverrun.Thinkparachutecordsandsuspensionbridgecables.A steady{{U}}?60?{{/U}}ofspidersilkwouldbeworthbillionsof dollars—buthowtoproduceit?Harvestingsilkonspiderfarmsdoesnot {{U}}?61?{{/U}}becausetheterritorialarthropodshaveatendencyto devourtheirneighbors.??Nowscientistsatthebiotechnology companyNexiaarespinningartificialsilkmodeledafterGoldernOrbdragline. The{{U}}?62?{{/U}}step:extractsilk-makinggenesfromthespiders. Nextimplantthegenesintogoateggcells.Thenannygoatsthatgrowfromthe eggssecretedraglinesilkproteinsintheir{{U}}?63?{{/U}}.The younggoatspassonthesilk-makinggenewithout{{U}}?64?{{/U}}help fromussaysNexiapresidentJeffreyTurner.?Nexiaisstillperfecting thespinningprocessbuttheyhopeartificialspidersilkwillsoonbesnagging customers{{U}}?65?{{/U}}therealthingsnags bugs.
Theboywasseriouslywoundedintheaccident.
OnAntibodies Substancesforeigntothebodysuchasdisease-causingbacteriaandvirusesandotherinfectiousagentsarerecognizedbythebodysimmunesystemasinvaders.Ournaturaldefensesagainsttheseinfectiousagentsareantibodiesproteinsthatseekouttheantigens抗原andhelpdestroythem. Antibodieshavetwoveryusefulcharacteristics.Firsttheyareextremelyspecific;thatiseachantibodybindstoandattacksoneparticularantigen.Secondsomeantibodiesonceactivatedbytheoccurrenceofadiseasecontinuetoconferresistanceagainstthatdisease.Classicexamplearetheantibodiestothechildhooddiseasesofchickenpox水痘andmeasles. Thesecondcharacteristicofantibodiesmakesitpossibletodevelopvaccines.Avaccine痘苗isapreparationofkilledorweakenedbacteriaorvirusesthatwhenintroducedintothebodystimulatestheproductionofantibodiesagainsttheantigensitcontains. Itisthefirsttraitofantibodiestheirspecificitythatmakesmonoclonalantibodytechnologysovaluable.Notonlycanantibodiesbeusedtherapeutically在治疗上toprotectagainstdisease;theycanalsohelpto.diagnoseawidevarietyofillnessesandcandetectthepresenceofdrugsviralandbacterialproductsandotherunusualorabnormalsubstancesintheblood. Givensuchadiversityofusesforthesediseased-fightingsubstancestheirproductioninpurequantitieshaslongbeenthefocusofscientificinvestigation.Theconventionalmethodwastoinjectalaboratoryanimalwithanantigenandthenafterantibodieshadbeenformedcollectthoseantibodiesfromthebloodserum血清Antibodycontainingbloodserumiscalledantiserum抗血清.Therearetwoproblemswiththismethod:Ityieldsantiserumthatcontainsundesiredsubstancesanditprovidesaverysmallamountofusableantibody. Monoclonalantibodytechnologyallowsustoproducelargeamountsofpureantibodies.inthefollowingway:wecanobtaincellsthatproduceantibodiesnaturally;wealsohaveavailableaclassofcellsthatcangrowcontinuallyincellculture培养.Ifweformahybrid混血儿thatcombinesthecharacteristicofimmortality永生withtheabilitytoproducethedesiredsubstancewewouldhaveineffectafactorytoproduceantibodiesthatworkaroundtheclock. Inmonoclonalantibodytechnologytumorcellsthatcanreplicate重复endlesslyarefusedwithmammaliancellsthatproduceanantibody.Theresultofthiscellfusionisahybridoma杂交瘤whichwillcontinuallyproduceantibodies.Theseantibodiesarecalledmonoclonalbecausetheycomefromonlyonetypeofcellthehybridomacell;antibodiesproducedbyconventionalmethodsontheotherhandarederivedfrompreparationscontainingmanykindsofcellsandhencearecalledpolyclonal.Anexampleofhowmonoclonalantibodiesarederivedisdescribedbelow. Amyelomaisatumorofthebonemarrow骨髓thatcanbeadaptedtogrowpermanendyincellculture.Whenmyelomacellswerefusedwithantibody-producingmammalianspleencellsitwasfoundthattheresultinghybridcellsorhybridomasproducedlargeamountsofmonoclonal骨髓瘤antibody.Thisproductofcellfusioncombinedthedesiredqualitiesofthetwodifferenttypesofcells:theabilitytogrowcontinuallyandtheabilitytoproducelargeamountsofpureantibody. Becauseselectedhybridcellsproduceonlyonespecificantibodytheyaremorepurethanthepolyclonalantibodiesproducedbyconventionaltechniques.Theyarepotentiallymoreeffectivethanconventionaldrugsinfightingdiseasesincedrugsattacknotonlytheforeignsubstancebutthebody’sowncellsaswellsometimesproducingundesirablesideeffectssuchasnausea恶心andallergicreactions.Monoclonalantibodiesattackthetargetmoleculeandonlythetargetmoleculewithnoorgreatlydiminishedsideeffects. Thepolyclonalantibodiesaredifferentfromthemonoclonalonesinallthefollowingwaysexceptthat______.
AmericansDecrease IncreasinglyhistoriansareblamingdiseasesimportedfromtheOldWorldforthestaggeringdisparity不同betweentheindigenous本土的populationofAmericain1492—newestimatesofwhichsoarashighas100millionorapproximatelyone-sixthofthehumanraceatthattime—andthefewmillionfull-bloodedNativeAmericansaliveattheendofthenineteenthcentury.Thereisnodoubtthatchronicdiseasewasanimportantfactorintheprecipitous险峻的declineanditishighlyprobablethatthegreatestkillerwasepidemicdiseaseespeciallyasmanifestedinvirgin-soil处女地epidemics. Virgin-soilepidemicsarethoseinwhichthepopulationsatriskhavehadnopreviouscontactwiththediseasesthatstrikethemandarethereforeimmunologically免疫学的almostdefenseless.Thatvirgin-soilepidemicswereimportantinAmericanhistoryisstronglyindicatedbyevidencethatanumberofdangerousmaladies病—smallpoxmeasles麻疹malaria疟病yellowfeverandundoubtedlyseveralmore—wereunknowninthepre-ColumbianNewWorld.TheeffectsoftheirsuddenintroductionaredemonstratedintheearlychroniclesofAmericawhichcontainreportsofhorrendous可怕的epidemicsandsteeppopulationdeclinesconfirmedinmanycasesbyrecentequantitativeanalysesofSpanishtributerecordsandothersources.TheevidenceprovidedbythedocumentsofBritishandFrenchcoloniesisnotasdefinitivebecausetheconquerorsofthoseareasdidnotestablishpermanentsettlementsandbegintokeepcontinuousrecordsuntiltheseventiethcenturybywhichtimetheworstepidemicshadprobablyalreadytakenplace.FurthermoretheBritishtendedtodrivethenativepopulationsawayratherthanenslavingthemastheSpaniardsdidsothattheepidemicsofBritishAmericaoccurredbeyondtherangeofcolonistsdirectobservation. EvensothesurvivingrecordsofNorthAmericadocontainreferencestodeadlyepidemicsamongtheindigenouspopulation.In1616—1619anepidemicpossiblyofbubonicorpneumonic肺的plague瘟疫sweptcoastalNewEnglandkillingasmanyasnineoutoften.Duringthe1630’’ssmall-poxthediseasemostfataltotheNativeAmericanpeopleeliminatedhalfthepopulationoftheHuronandIroquoisconfederations.Inthe1820’’sfeverdevastatedthepeopleoftheCoulumbiaRiverareakillingeightoutoftenofthem. UnfortunatelythedocumentationoftheseandotherepidemicsisslightandfrequentlyunreliableanditisnecessarytosupplementwhatlittlewedoknowwithevidencefromrecentepidemicsamongNativeAmericans.Forexamplein1952anoutbreakofmeaslesamongtheNativeAmericaninhabitantsofUngavaBay.Quebecaffected99percentofthepopulationandkilled7percenteventhoughsomehadthebenefitofmodernmedicine.Casessuchasthisdemonstratethatevendiseasesthatarenotnormallyfatalcanhavedevastatingconsequenceswhentheystrikeanimmunologicallydefenselesscommunity. Theprimarypurposeofthepassageisto______.
Shelongedtobeenviedandsoughtafter.
Language Whenmostofusthinkaboutlanguagewethinkfirstaboutwords.Thusthehardestpartoflearningaforeignlanguagemayseemtobememorizing【51】vocabulary;whenweobserveachildfirstacquiringspeechwetalkofhisprogress【52】amatteroflearningnewwords.Wearealso【53】tofeelthattheadultspeakerwiththelargestvocabularyhasthebest【54】ofEnglish.Tothink【55】alanguageasjustastockofwordsis【56】quitewrong.Wordsalonedonot【57】alanguage;agrammaris【58】tocombinetheminsomeintelligibleway.Moreoverwordsarerelativelyeasytolearnandindeedallofusgo【59】learningthemallour【60】.Theyarealsothe【61】stablepartoflanguage.Wordscomeinto【62】changetheirpronunciationsandmeaningsanddisappearcompletelyallwithcomparativeease.Yetitistruethatthe【63】isfocusoflanguage.Itisinwords【64】soundsandmeaningsinterlocktoallowusto【65】withoneanotheranditiswordsthatwearrangetogethertomakesentencesconversationsanddiscourseofallkinds.Thuswehaveaparadoxinthatthemostshort-livedpartoflanguageisalsothecentrewheremeaningpronunciationandgrammarcometogether.
AmericansDecrease IncreasinglyhistoriansareblamingdiseasesimportedfromtheOldWorldforthestaggeringdisparity不同betweentheindigenous本土的populationofAmericain1492—newestimatesofwhichsoarashighas100millionorapproximatelyone-sixthofthehumanraceatthattime—andthefewmillionfull-bloodedNativeAmericansaliveattheendofthenineteenthcentury.Thereisnodoubtthatchronicdiseasewasanimportantfactorintheprecipitous险峻的declineanditishighlyprobablethatthegreatestkillerwasepidemicdiseaseespeciallyasmanifestedinvirgin-soil处女地epidemics. Virgin-soilepidemicsarethoseinwhichthepopulationsatriskhavehadnopreviouscontactwiththediseasesthatstrikethemandarethereforeimmunologically免疫学的almostdefenseless.Thatvirgin-soilepidemicswereimportantinAmericanhistoryisstronglyindicatedbyevidencethatanumberofdangerousmaladies病—smallpoxmeasles麻疹malaria疟病yellowfeverandundoubtedlyseveralmore—wereunknowninthepre-ColumbianNewWorld.TheeffectsoftheirsuddenintroductionaredemonstratedintheearlychroniclesofAmericawhichcontainreportsofhorrendous可怕的epidemicsandsteeppopulationdeclinesconfirmedinmanycasesbyrecentequantitativeanalysesofSpanishtributerecordsandothersources.TheevidenceprovidedbythedocumentsofBritishandFrenchcoloniesisnotasdefinitivebecausetheconquerorsofthoseareasdidnotestablishpermanentsettlementsandbegintokeepcontinuousrecordsuntiltheseventiethcenturybywhichtimetheworstepidemicshadprobablyalreadytakenplace.FurthermoretheBritishtendedtodrivethenativepopulationsawayratherthanenslavingthemastheSpaniardsdidsothattheepidemicsofBritishAmericaoccurredbeyondtherangeofcolonistsdirectobservation. EvensothesurvivingrecordsofNorthAmericadocontainreferencestodeadlyepidemicsamongtheindigenouspopulation.In1616—1619anepidemicpossiblyofbubonicorpneumonic肺的plague瘟疫sweptcoastalNewEnglandkillingasmanyasnineoutoften.Duringthe1630’’ssmall-poxthediseasemostfataltotheNativeAmericanpeopleeliminatedhalfthepopulationoftheHuronandIroquoisconfederations.Inthe1820’’sfeverdevastatedthepeopleoftheCoulumbiaRiverareakillingeightoutoftenofthem. UnfortunatelythedocumentationoftheseandotherepidemicsisslightandfrequentlyunreliableanditisnecessarytosupplementwhatlittlewedoknowwithevidencefromrecentepidemicsamongNativeAmericans.Forexamplein1952anoutbreakofmeaslesamongtheNativeAmericaninhabitantsofUngavaBay.Quebecaffected99percentofthepopulationandkilled7percenteventhoughsomehadthebenefitofmodernmedicine.Casessuchasthisdemonstratethatevendiseasesthatarenotnormallyfatalcanhavedevastatingconsequenceswhentheystrikeanimmunologicallydefenselesscommunity. AccordingtothepassagetheBritishcolonialistsdifferedfromtheSpanishcolonialistsinthattheformer______.
CigarsInstead? Smokingoneortwocigarsadaydoublestheriskofcancersoftheliptonguemouthandthroataccordingtoagovernmentstudy. DailycigarsalsoincreasetheriskoflungcancerandcanceroftheesophagusandincreasetheriskofcancerofthelarynxvoiceboxsixfoldsayresearchersattheNationalCancerInstituteinBethesdaMaryland. Inadditionthereportrevealedthatsmokingthreeorfourcigarsadayincreasedtheriskoforalcancerto8.5timestheriskfornonsmokersandtheriskofesophagealcancerbyfourtimestheriskofnonsmokers. ThehealtheffectsofsmokingcigarsisoneofeightsectionsofthearticleCigars:HealthEffectsandTrends.Theresearchersreportthatcomparedwithacigarettealargecigaremitsupto90timesasmuchcarcinogenictobacco-specificnitrosamines ThisarticleprovidesclearandinvaluableinformationaboutthedisturbingincreaseincigaruseandthesignificantpublichealthconsequencesforthecountrysaidDr.RichardKlausnerdirectoroftheNationalCancerInstituteinastatement. Thedataareclear-theharmfulsubstancesandcarcinogensincigarsmokelikecigarettesareassociatedwiththeincreasedrisksofseveralkindsofcancersaswellasheartandlungdiseasesheadded.Inotherwordscigarsarenotsafealternativestocigarettesandmaybeaddictive. Tothoseindividualswhomaybethinkingaboutsmokingcigarsouradvicesis—don’’t.TothosecurrentlysmokingcigarsquittingistheonlywaytoeliminatecompletelythecancerheartandlungdiseaseriskswarnedKlausner. AccordingtoaNationalCancerInstitutepressreleasetherehaven’’tbeenanystudiesonthehealtheffectsonnonsmokersatcigarsocialeventsbut...asignificantbodyofevidenceclearlydemonstratesanincreasedlungcancerriskfromsecondhandsmoke. Whatisthedoctors’advicetothosecigar-smokers?
Dyslexia Asmanyas20%ofallchildrenintheUnitedStatessufferfromsomeformofthelearningdisorder2calleddyslexia. Expertsondyslexiasaythattheproblemisnotadisease.Theysaythatpersonswithdyslexiauseinformationinadifferentway.Oneoftheworldsgreatthinkersandscientists.AlbertEinsteinwasdyslexic.Einsteinsaidthatheneverthoughtinwordsthewaythatmostpeopledo.Hesaidthathethoughtinpicturesinstead. TheAmericaninventorThomasEdisonwasalsodyslexic.DyslexiafirstwasrecognizedinEuropeandtheUnitedStatesmorethan80yearsago.Manyyearspassedbeforedoctorsdiscoveredthatpersonswiththedisorderwerenotmentallyslowordisabled.Thedoctorsfoundthatthebrainsofpersonswithdyslexiaaredifferent. Inmostpeopletheleftsideofthebrain—thepartthatcontrolslanguageislargerthantherightside.Inpersonswithdyslexiatherightsideofthebrainisbigger.Doctorsarenotsurewhatcausesthisdifference.Howeverresearchhasshownthatdyslexiaismorecommoninmalesthaninfemalesanditisfoundmoreofteninpersonswhoarelefthanded4.Nooneknowsthecauseofdyslexiabutsomescientistsbelievethatitmayresultfromchemicalchangesinababy’’sbodylongbeforeitisborn.Theyaretryingtofindwaystoteachpersonswithdyslexia.Dyslexicpersonsthinkdifferentlyandneedspecialkindsofteachinghelp.Aftertheyhavesolvedtheirproblemswithlanguagetheyoftenshowthemselvestobeespeciallyintelligentorcreative. Generallyspeakingdyslexiaismorecommoninleft-handedmalesthaninright-handedfemales.
{{*HTML*}}下面的短文有15处空白请根据短文内容为每处空白确定1个最佳选项 ?? WonderWebs??Spiderwebs aremorethanhomesandtheyareingenioustraps.Andtheworld’sbestweb spinnermaybetheGoldernOrbWeaverspider.ThefemaleOrbWeaverspinsaweb offibersthinenoughtobeinvisibletoinsect?yet{{U}}?51 ?{{/U}}enoughtosnareaflyingbirdwithoutbreaking.??The secretoftheweb’sstrength.Atypeofsuper-resilient{{U}}?52?{{/U}} calleddragline.Whenthefemalespiderisreadyto{{U}}?53?{{/U}}the web’sspokesandframesheusesherlegstodrawtheairythreadoutthrougha hollownozzleinherbelly.Draglineisnotstickysothespidercanraceback andforthalong{{U}}?54?{{/U}}tospintheweb’strademark spiral.??Unlikesomespidersthatweaveanewwebeverydaya GoldenOrbWeaver{{U}}?55?{{/U}}herhandiworkuntilitfailsapart sometimesnotfortwoyears.Thesilkythreadisfivetimesstrongerthansteel byweightandabsorbstheforceofanimpactthreetimesbetterthanKevlara highstrengthhuman-made{{U}}?56?{{/U}}usedinbullet-proofvests. ?Andthankstoitshightensilestrengthortheabilitytoresistbreaking underthepullingforcecalledtensionasinglestrandcanstretchupto40 percentlongerthanitsoriginal{{U}}?57?{{/U}}andsnapbackaswell asnew.Nohuman-madefiberevencomes{{U}}?58?{{/U}}.? ?Itisno{{U}}?59?{{/U}}manufacturersareclamoringforspider silk.Intheconsumerpipeline:high-performancefabricsforathletesand stockingsthatneverrun.Thinkparachutecordsandsuspensionbridgecables.A steady{{U}}?60?{{/U}}ofspidersilkwouldbeworthbillionsof dollars—buthowtoproduceit?Harvestingsilkonspiderfarmsdoesnot {{U}}?61?{{/U}}becausetheterritorialarthropodshaveatendencyto devourtheirneighbors.??Nowscientistsatthebiotechnology companyNexiaarespinningartificialsilkmodeledafterGoldernOrbdragline. The{{U}}?62?{{/U}}step:extractsilk-makinggenesfromthespiders. Nextimplantthegenesintogoateggcells.Thenannygoatsthatgrowfromthe eggssecretedraglinesilkproteinsintheir{{U}}?63?{{/U}}.The younggoatspassonthesilk-makinggenewithout{{U}}?64?{{/U}}help fromussaysNexiapresidentJeffreyTurner.?Nexiaisstillperfecting thespinningprocessbuttheyhopeartificialspidersilkwillsoonbesnagging customers{{U}}?65?{{/U}}therealthingsnags bugs.
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