首页
试卷库
试题库
当前位置：
X题卡
>
所有题目
>
题目详情
Most of the dreadful eruptions of Mount Saint Helens took place in early May.
查看本题答案
包含此试题的试卷
理工类《单选题》真题及答案
点击查看
你可能感兴趣的试题
A．thanmorerecentonesB．thekillingefficiencyforolder
BlastsfromthePast??1?Volcanoesweredestructiveinanc
BlastsfromthePast??1?Volcanoesweredestructiveinanc
BlastsfromthePast??1?Volcanoesweredestructiveinanc
BlastsfromthePast1Volcanoesweremoredestructiveinan
BlastsfromthePast??1?Volcanoesweredestructiveinanc
BlastsfromthePast1Volcanoesweremoredestructiveinan
Theyhavebeenlivingunderthemost{{U}}appalling{{/U}}
dreadful
bad
unpleasant
poor
BlastsfromthePast??1?Volcanoesweredestructiveinanc
BlastsfromthePast1Volcanoesweremoredestructiveinan
Whatdreadfulweatherwehavethesedays!
terrible
wonderful
nice
cold
Peoplehavealwaysbeenbothfascinatedbythespectacleof
magic
force
display
purpose
Thevolcanoeruptionsarefound________aroundthePacifi
almost
nearly
most
mostly
BlastsfromthePast1Volcanoesweremoredestructiveinan
What{{U}}dreadful{{/U}}weatherwehavethesedays!
terrible
wonderful
nice
cold
BlastsfromthePast??1?Volcanoesweredestructiveinanc
BlastsfromthePast??1?Volcanoesweredestructiveinanc
A.thanmorerecentonesB.thekillingefficiencyforolder
BlastsfromthePast??1?Volcanoesweredestructiveinanc
Theyhavebeenlivingunderthemostappallingconditionsf
dreadful
bad
unpleasant
poor
热门试题
更多
Therearea{{U}}limited{{/U}}numberofbooksonthissubjectinthelibrary.
{{*HTML*}}??阅读下面的短文文中有15处空白每处空白给出了4个选项请根据短文的内容从4个选项中选择1个最佳答案 {{B}}??????? ??????????? ??DriedFoods{{/B}}??Centuriesagomandiscoveredthat removingmoisture{{U}}?51?{{/U}}foodhelpedtopreserveitandthat theeasiestwaytodothiswastoexposethefoodtothesunandwind.In this{{U}}?52?{{/U}}theNorthAmericanIndiansproducedriedmeatand makeitintocakestheScandinaviansmake{{U}}?53?{{/U}}fishandthe Arabsmakedrieddates.??Allfoodscontain{{U}}?54 ?{{/U}}cabbageandotherleafvegetablescontainasmuchas93%water ?potatoesandotherrootvegetables80%leanmeat75%andfishanything from80%to60%depending{{U}}?55?{{/U}}howfattyitis.Ifthiswater is{{U}}?56?{{/U}}theactivityofthebacteriawhichcausesfoodto gobadisstopped.??Nowdaymostfoodsaredriedmechanically. Themostcommon{{U}}?57?{{/U}}ofsuchdryingistoputfoodin chambers.Thisistheusualmethodfordryingsuchthings{{U}}?58 ?{{/U}}vegetablesmincedmeatandfish.??Liquidssuchas milkcoffeeteasoupsandeggsmaybedried{{U}}?59?{{/U}}pouring themoveraheatedhorizontalsteelcylinderorbysprayingthemintoachamber through{{U}}?60?{{/U}}acurrentofhotairpasses.Inthefirst{{U}} ?61?{{/U}}thedriedmaterialisscrapedofftherollerasathin filmwhichisthenbrokenupintosmallpiecesthoughstillrelativelycoarse flakes.Inthesecondprocessitfallstothebottomofthechamberasafine powder.Where{{U}}?62?{{/U}}piecesofmeatandvegetablesare requiredasinsouptheingredientsaredriedseparatelyandthen mixed.??Driedfoodstakeuplessroomandweighless{{U}} ?63?{{/U}}thesamefoodpackedincanorfrozen?andthey are{{U}}?64?{{/U}}toclimbersexplorersandsoldiersinbattlewho havelittlestoragespace.Theyarealsopopularwithhousewives{{U}}?65 ?{{/U}}ittakessolittletimetocookthem.Usuallyitisjustamatterof replacingthedried-outmoisturewithboiling water.
Thistableisstrongand{{U}}durable{{/U}}.
{{*HTML*}}??A.fallasleepagain.??B.becomemoreenergetic thefollowingday??C.sleeplessthan7hours??D. confirmthoseseriousconsequences??E.suffersleep problems??F.sleepmorethan8hoursOneofthesleepproblemsiswakinginthemiddleofthenightunableto______.
{{*HTML*}}下面的短文后列出了7个句子请根据短文的内容对每个句子做出判断如果该句提的是正确信息请选择A如果该句提的是错误信息请选择B如果该句的信息文中没有提及请选择C ComputerMouse??The basiccomputermouseisanamazinglycleverinventionwitharelativelysimple designthatallowsustopointatthingsonthecomputeranditisvery productive.Thinkofallthethingsyoucandowithamouselikeselectingtext forcopyingandpasting涂drawingandevenscrollingonthepagewiththe newermicewiththewheel.Mostofususethecomputermousedailywithout stoppingtothinkhowitworksuntilitgetsdirtyandwehavetolearnhowto cleanit.Welearntopointatthingsbeforewelearntospeaksothemouseis averynaturalpointingdevice.?Othercomputerpointingdevicesinclude lightpensgraphics图形tabletsandtouchscreensbutthemouseisstillour workhorse.??Thecomputermousewasinventedin1964byDouglas EnglehartofStanfordUniversity.Ascomputerscreensbecamemorepopularand arrowkeyswereusedtomovearoundabodyoftextitbecameclearthata pointingdevicethatallowedeasiermotionthroughthetextandevenselection oftextwouldbeveryuseful.TheintroductionofthemousewiththeAppleLisa computerin1983reallystartedthecomputerpublicontheroadtorelyingon themouseforroutine常规computertasks.??Howdoesthemouse work?Wehavetostartatthebottomsothinkupsidedownfornow.Itall startswiththemouseball.Asthemouseballinthebottomofthemouserolls overthemousepaditpressesagainstandturnstwoshafts轴.Theshaftsare conneectedtowheelswithseveralsmallholesinthem.Thewheelshaveapairof smallelectroniclight-emittingdevicescalledlight-emittingdiodesLED mountedoneitherside.OneLEDsendsalightbeamtotheLEDontheotherside. AsthewheelsspinandaholerotatesbythelightbeamgetsthroughtotheLED ontheotherside.Butamomentlaterthelightbeamisblockeduntilthenext holeisinplace.TheLEDdetects发现achangingpatternoflightconvertsthe patternintoanelectronicsignalandsendsthesignal发信号tothecomputer throughwiresinacablethatgoesoutthemousebody.Thiscableisthetail thathelpsgivethemouseitsname.Thecomputerinterpretsthesignaltotell itwheretopositionthecursoronthecomputerscreen.??Sofar wehaveonlydiscussedthebasiccomputermousethatmostofyouprobablyhave orhaveused.Oneproblemwiththisdesignisthatthemousegetsdirtyasthe ballrollsoverthesurfaceandpicksupdirt.Eventuallyyouhavetocleanyour mouse.Theneweropticalmiceavoidthisproblembyhavingnomoving parts.ThekeycomponentsofacomputermousearethetwoLEDs.
{{*HTML*}}下面的短文后列出了7个句子请根据短文的内容对每个句子做出判断如果该句提的是正确信息请选择A如果该句提的是错误信息请选择B如果该句的信息文中没有提及请选择C ComputerMouse??The basiccomputermouseisanamazinglycleverinventionwitharelativelysimple designthatallowsustopointatthingsonthecomputeranditisvery productive.Thinkofallthethingsyoucandowithamouselikeselectingtext forcopyingandpasting涂drawingandevenscrollingonthepagewiththe newermicewiththewheel.Mostofususethecomputermousedailywithout stoppingtothinkhowitworksuntilitgetsdirtyandwehavetolearnhowto cleanit.Welearntopointatthingsbeforewelearntospeaksothemouseis averynaturalpointingdevice.?Othercomputerpointingdevicesinclude lightpensgraphics图形tabletsandtouchscreensbutthemouseisstillour workhorse.??Thecomputermousewasinventedin1964byDouglas EnglehartofStanfordUniversity.Ascomputerscreensbecamemorepopularand arrowkeyswereusedtomovearoundabodyoftextitbecameclearthata pointingdevicethatallowedeasiermotionthroughthetextandevenselection oftextwouldbeveryuseful.TheintroductionofthemousewiththeAppleLisa computerin1983reallystartedthecomputerpublicontheroadtorelyingon themouseforroutine常规computertasks.??Howdoesthemouse work?Wehavetostartatthebottomsothinkupsidedownfornow.Itall startswiththemouseball.Asthemouseballinthebottomofthemouserolls overthemousepaditpressesagainstandturnstwoshafts轴.Theshaftsare conneectedtowheelswithseveralsmallholesinthem.Thewheelshaveapairof smallelectroniclight-emittingdevicescalledlight-emittingdiodesLED mountedoneitherside.OneLEDsendsalightbeamtotheLEDontheotherside. AsthewheelsspinandaholerotatesbythelightbeamgetsthroughtotheLED ontheotherside.Butamomentlaterthelightbeamisblockeduntilthenext holeisinplace.TheLEDdetects发现achangingpatternoflightconvertsthe patternintoanelectronicsignalandsendsthesignal发信号tothecomputer throughwiresinacablethatgoesoutthemousebody.Thiscableisthetail thathelpsgivethemouseitsname.Thecomputerinterpretsthesignaltotell itwheretopositionthecursoronthecomputerscreen.??Sofar wehaveonlydiscussedthebasiccomputermousethatmostofyouprobablyhave orhaveused.Oneproblemwiththisdesignisthatthemousegetsdirtyasthe ballrollsoverthesurfaceandpicksupdirt.Eventuallyyouhavetocleanyour mouse.Theneweropticalmiceavoidthisproblembyhavingnomoving parts.ThemostdurablecomputermiceonsalearetheIBMones.
Maryhas{{U}}blended{{/U}}theingredients.
{{*HTML*}}??阅读下面的短文文中有15处空白每处空白给出了4个选项请根据短文的内容从4个选项中选择1个最佳答案 {{B}}??????? ??????????? ??DriedFoods{{/B}}??Centuriesagomandiscoveredthat removingmoisture{{U}}?51?{{/U}}foodhelpedtopreserveitandthat theeasiestwaytodothiswastoexposethefoodtothesunandwind.In this{{U}}?52?{{/U}}theNorthAmericanIndiansproducedriedmeatand makeitintocakestheScandinaviansmake{{U}}?53?{{/U}}fishandthe Arabsmakedrieddates.??Allfoodscontain{{U}}?54 ?{{/U}}cabbageandotherleafvegetablescontainasmuchas93%water ?potatoesandotherrootvegetables80%leanmeat75%andfishanything from80%to60%depending{{U}}?55?{{/U}}howfattyitis.Ifthiswater is{{U}}?56?{{/U}}theactivityofthebacteriawhichcausesfoodto gobadisstopped.??Nowdaymostfoodsaredriedmechanically. Themostcommon{{U}}?57?{{/U}}ofsuchdryingistoputfoodin chambers.Thisistheusualmethodfordryingsuchthings{{U}}?58 ?{{/U}}vegetablesmincedmeatandfish.??Liquidssuchas milkcoffeeteasoupsandeggsmaybedried{{U}}?59?{{/U}}pouring themoveraheatedhorizontalsteelcylinderorbysprayingthemintoachamber through{{U}}?60?{{/U}}acurrentofhotairpasses.Inthefirst{{U}} ?61?{{/U}}thedriedmaterialisscrapedofftherollerasathin filmwhichisthenbrokenupintosmallpiecesthoughstillrelativelycoarse flakes.Inthesecondprocessitfallstothebottomofthechamberasafine powder.Where{{U}}?62?{{/U}}piecesofmeatandvegetablesare requiredasinsouptheingredientsaredriedseparatelyandthen mixed.??Driedfoodstakeuplessroomandweighless{{U}} ?63?{{/U}}thesamefoodpackedincanorfrozen?andthey are{{U}}?64?{{/U}}toclimbersexplorersandsoldiersinbattlewho havelittlestoragespace.Theyarealsopopularwithhousewives{{U}}?65 ?{{/U}}ittakessolittletimetocookthem.Usuallyitisjustamatterof replacingthedried-outmoisturewithboiling water.
Theyagreedto{{U}}modify{{/U}}theirpolicy.
{{*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 TheBuildingofthePyramids? ?Theoldeststonebuildingsintheworldarethepyramids.Theyhavestood fornearly5000yearsanditseemslikethat{{U}}?46?{{/U}}.There areovereightyofthemscattered分散的alongthebanksoftheNilesomeof whicharedifferentinshapefromthetruepyramids.Themostfamousofthese aretheSteppyramidandtheBentpyramid.??Someofthe pyramidsstilllookmuchthesameastheymusthavedonewhentheywerebuilt thousandsofyearsago.Mostofthedamagesufferedbytheothershasbeenat thehandsofmenwhowerelookingfortreasureormoreoften{{U}}?47 ?{{/U}}.ThedryclimateofEgypthashelpedtopreservethepyramidsand theirveryshape{{U}}?48?{{/U}}.Thesearegoodreasonswhytheycan stillbeseentodaybutperhapsthemostimportantisthattheywereplannedto lastforever.??Itispracticallycertainthatplansweremade forthebuildingofthepyramids{{U}}?49?{{/U}}.Howeverthereareno writingsorpicturestoshowushowtheEgyptiansplannedorbuiltthepyramids themselves.Consequentlyweareonlyabletoguessatthemethodsused. Neverthelessbyexaminingtheactualpyramidsandvarioustoolswhichhavebeen foundarchaeologists考古学家haveformedafairlyclearpictureof them.??Onethingiscertaintheremusthavebeenmonthsof carefulplanning{{U}}?50?{{/U}}.Thefirstthingtheyhadtodowasto chooseasuitableplace.Youmaythinkthiswouldhavebeeneasywithmilesand milesofemptydesertaroundbutapyramidcouldnotbebuiltjustanywhere. Certainruleshadtobefollowedandcertainproblemshadtobe overcome.??A.forstonetouseinmodernbuildings? ?B.hasmadethemlesslikelytofallintoruin??C.before theycouldbegintobuild??D.becausetheplansofotherlarge workshavefortunatelybeenpreserved??E.whilebuildingthe pyramids??F.theywillcontinuetostandforthousandsofyears yet
{{*HTML*}}? ?下面的短文后有2项测试任务1第23～26题要求从所给的6个选项中为第3～6段每段选择1个最佳标题2第27～30题要求从所给的6个选项中为每个句子确定1个最佳选项? ? MoreThan8HoursSleepTooMuchofaGood Thing??Althoughthedangersoftoolittlesleep arewidelyknownnewresearchsuggeststhatpeoplewhosleeptoomuchmayalso suffertheconsequences.??InvestigatorsattheUniversityof CaliforniainSanDiegofoundthatpeoplewhoclockup9or10hourseach weeknightappeartohavemoretroublefallingandstayingasleepaswellasa numberofothersleepproblemsthanpeoplewhosleep8hoursanight.People whosleptonly7hourseachnightalsosaidtheyhadmoretroublefallingasleep andfeelingrefreshedafteranight’ssleepthan8-hoursleepers.? ?ThesefindingswhichDr.DanielKripkereportedinthejournal PsychosomaticMedicinedemonstratethatpeoplewhowanttogetagoodnight’s restmaynotneedtosetasidemorethan8hoursanight.Headdedthatit mightbeagoodideaforpeoplewhosleepmorethan8hourseachnightto considerreducingtheamountoftimetheyspendinbedbutcautionedthatmore researchisneededtoconfirmthis.??Previousstudieshaveshown thepotentialdangersofchronicshortagesofsleep--forinstanceonereport demonstratedthatpeoplewhohabituallysleeplessthan7hourseachnighthave ahigherriskofdyingwithinafixedperiodthanpeoplewhosleep more.??ForthecurrentreportKripkereviewedtheresponsesof 1004adultstosleepquestionnairesinwhichparticipantsindicatedhowmuch theysleptduringtheWeekandwhethertheyexperiencedanysleepproblems. Sleepproblemsincludedwakinginthemiddleofthenightarisingearlyinthe morningandbeingunabletofallbacktosleepandhavingfatigueinterfere withday-to-dayfunctioning.??Kripkefoundthatpeoplewhoslept between9and10hourseachnightweremorelikelytoreportexperiencingeach sleepproblemthanpeoplewhoslept8hours.InaninterviewKripkenotedthat longsleepersmaystruggletogetrestatnightsimplybecausetheyspendtoo muchtimeinbed.Asevidenceheaddedthatonewaytohelpinsomniaisto spendlesstimeinbed.Itstandstoreasonthatifapersonspendstoolonga timeinbedthenthey’llspendahigherpercentageoftimeawake.he said. ??A.Keprike’sResearchTool??B.Dangersof HabitualShortagesofSleep??C.CriticismonKripke’s Report??D.AwayofOvercomingInsomnia??E.Sleep ProblemsofLongandShortSleepers??F.ClassificationofSleen ProblemsParagraph2______
{{*HTML*}}??阅读下面的短文文中有15处空白每处空白给出了4个选项请根据短文的内容从4个选项中选择1个最佳答案 {{B}}??????? ??????????? ??DriedFoods{{/B}}??Centuriesagomandiscoveredthat removingmoisture{{U}}?51?{{/U}}foodhelpedtopreserveitandthat theeasiestwaytodothiswastoexposethefoodtothesunandwind.In this{{U}}?52?{{/U}}theNorthAmericanIndiansproducedriedmeatand makeitintocakestheScandinaviansmake{{U}}?53?{{/U}}fishandthe Arabsmakedrieddates.??Allfoodscontain{{U}}?54 ?{{/U}}cabbageandotherleafvegetablescontainasmuchas93%water ?potatoesandotherrootvegetables80%leanmeat75%andfishanything from80%to60%depending{{U}}?55?{{/U}}howfattyitis.Ifthiswater is{{U}}?56?{{/U}}theactivityofthebacteriawhichcausesfoodto gobadisstopped.??Nowdaymostfoodsaredriedmechanically. Themostcommon{{U}}?57?{{/U}}ofsuchdryingistoputfoodin chambers.Thisistheusualmethodfordryingsuchthings{{U}}?58 ?{{/U}}vegetablesmincedmeatandfish.??Liquidssuchas milkcoffeeteasoupsandeggsmaybedried{{U}}?59?{{/U}}pouring themoveraheatedhorizontalsteelcylinderorbysprayingthemintoachamber through{{U}}?60?{{/U}}acurrentofhotairpasses.Inthefirst{{U}} ?61?{{/U}}thedriedmaterialisscrapedofftherollerasathin filmwhichisthenbrokenupintosmallpiecesthoughstillrelativelycoarse flakes.Inthesecondprocessitfallstothebottomofthechamberasafine powder.Where{{U}}?62?{{/U}}piecesofmeatandvegetablesare requiredasinsouptheingredientsaredriedseparatelyandthen mixed.??Driedfoodstakeuplessroomandweighless{{U}} ?63?{{/U}}thesamefoodpackedincanorfrozen?andthey are{{U}}?64?{{/U}}toclimbersexplorersandsoldiersinbattlewho havelittlestoragespace.Theyarealsopopularwithhousewives{{U}}?65 ?{{/U}}ittakessolittletimetocookthem.Usuallyitisjustamatterof replacingthedried-outmoisturewithboiling water.
Wewilltakeyourrecentillnessinto{{U}}consideration{{/U}}whenmarkingyourexams.
{{*HTML*}}??阅读下面的短文文中有15处空白每处空白给出了4个选项请根据短文的内容从4个选项中选择1个最佳答案 {{B}}??????? ??????????? ??DriedFoods{{/B}}??Centuriesagomandiscoveredthat removingmoisture{{U}}?51?{{/U}}foodhelpedtopreserveitandthat theeasiestwaytodothiswastoexposethefoodtothesunandwind.In this{{U}}?52?{{/U}}theNorthAmericanIndiansproducedriedmeatand makeitintocakestheScandinaviansmake{{U}}?53?{{/U}}fishandthe Arabsmakedrieddates.??Allfoodscontain{{U}}?54 ?{{/U}}cabbageandotherleafvegetablescontainasmuchas93%water ?potatoesandotherrootvegetables80%leanmeat75%andfishanything from80%to60%depending{{U}}?55?{{/U}}howfattyitis.Ifthiswater is{{U}}?56?{{/U}}theactivityofthebacteriawhichcausesfoodto gobadisstopped.??Nowdaymostfoodsaredriedmechanically. Themostcommon{{U}}?57?{{/U}}ofsuchdryingistoputfoodin chambers.Thisistheusualmethodfordryingsuchthings{{U}}?58 ?{{/U}}vegetablesmincedmeatandfish.??Liquidssuchas milkcoffeeteasoupsandeggsmaybedried{{U}}?59?{{/U}}pouring themoveraheatedhorizontalsteelcylinderorbysprayingthemintoachamber through{{U}}?60?{{/U}}acurrentofhotairpasses.Inthefirst{{U}} ?61?{{/U}}thedriedmaterialisscrapedofftherollerasathin filmwhichisthenbrokenupintosmallpiecesthoughstillrelativelycoarse flakes.Inthesecondprocessitfallstothebottomofthechamberasafine powder.Where{{U}}?62?{{/U}}piecesofmeatandvegetablesare requiredasinsouptheingredientsaredriedseparatelyandthen mixed.??Driedfoodstakeuplessroomandweighless{{U}} ?63?{{/U}}thesamefoodpackedincanorfrozen?andthey are{{U}}?64?{{/U}}toclimbersexplorersandsoldiersinbattlewho havelittlestoragespace.Theyarealsopopularwithhousewives{{U}}?65 ?{{/U}}ittakessolittletimetocookthem.Usuallyitisjustamatterof replacingthedried-outmoisturewithboiling water.
{{*HTML*}}{{B}}第三篇{{/B}} ASunshadeforthePlanet? ?Evenwiththebestwillintheworldreducingourcarbonemissionsisnot goingtopreventglobalwarming.Ithasbecomeclearthatevenifwetakethe moststrongmeasurestocontrolemissionstheuncertainties不确定inour climatemodelsstillleaveopenthepossibilityofextremewarmingandrisesin sealevel.Atthesametimeresistancebygovernmentsandspecialinterest groupsmakesitquitepossiblethattheactionssuggestedbyclimatescientists mightnotbeimplemented执行soonenough.??Fortunatelyifthe worstcomestotheworstscientistsstillhaveafewtricksuptheirsleeves. Forthemostparttheyhavestronglyresisteddiscussingtheseoptionsforfear ofinvitingasenseofcomplacencythatmightthwarteffortstotackletheroot oftheproblem.Untilnowthatis.Agrowingnumberofresearchersaretakinga freshlookatlarge-scalegeoengineeringprojectsthatmightbeusedto counteract抵消globalwarming.IusetheanalogyofmethadonesaysStephen SchneideraclimateresearcheratStanfordUniversityinCaliforniawhowas amongthefirsttodrawattentiontoglobalwarming.Ifyouhaveaheroin addictthecorrecttreatmentishospitalizationandalongrehaB.Butifthey absolutelyrefusemethadoneisbetterthanheroin.??Basically theideaistoapplysunscreentothewholeplanet.Oneastronomerhascomeup witharadicalplantocoolEarth;launchtrillionsoffeather-lightdiscsinto spacewheretheywouldformavastcloudthatwouldblockthesun’srays.It’s controversialbutrecentstudiessuggesttherearewaystodeflectjustenough ofthesunlightreachingtheEarth’ssurfacetocounteractthewarmingproduced bythegreenhouseeffect.Globalclimatemodelsshowthatblockingjust1.8per centoftheincidentenergyinthesun’srayswouldcanceloutthewarming effectsproducedbyadoublingofgreenhousegasesintheatmosphere.Thatcould becrucialbecauseeventhemostsevereemissions-controlmeasuresbeing proposedwouldleaveuswithadoublingofcarbondioxidebytheendofthis centuryandthatwouldlastforatleastacentury more.WhatdoesStephenSchneidersayaboutaheroinaddictandmethadone?
{{*HTML*}}{{B}}第三篇{{/B}} ASunshadeforthePlanet? ?Evenwiththebestwillintheworldreducingourcarbonemissionsisnot goingtopreventglobalwarming.Ithasbecomeclearthatevenifwetakethe moststrongmeasurestocontrolemissionstheuncertainties不确定inour climatemodelsstillleaveopenthepossibilityofextremewarmingandrisesin sealevel.Atthesametimeresistancebygovernmentsandspecialinterest groupsmakesitquitepossiblethattheactionssuggestedbyclimatescientists mightnotbeimplemented执行soonenough.??Fortunatelyifthe worstcomestotheworstscientistsstillhaveafewtricksuptheirsleeves. Forthemostparttheyhavestronglyresisteddiscussingtheseoptionsforfear ofinvitingasenseofcomplacencythatmightthwarteffortstotackletheroot oftheproblem.Untilnowthatis.Agrowingnumberofresearchersaretakinga freshlookatlarge-scalegeoengineeringprojectsthatmightbeusedto counteract抵消globalwarming.IusetheanalogyofmethadonesaysStephen SchneideraclimateresearcheratStanfordUniversityinCaliforniawhowas amongthefirsttodrawattentiontoglobalwarming.Ifyouhaveaheroin addictthecorrecttreatmentishospitalizationandalongrehaB.Butifthey absolutelyrefusemethadoneisbetterthanheroin.??Basically theideaistoapplysunscreentothewholeplanet.Oneastronomerhascomeup witharadicalplantocoolEarth;launchtrillionsoffeather-lightdiscsinto spacewheretheywouldformavastcloudthatwouldblockthesun’srays.It’s controversialbutrecentstudiessuggesttherearewaystodeflectjustenough ofthesunlightreachingtheEarth’ssurfacetocounteractthewarmingproduced bythegreenhouseeffect.Globalclimatemodelsshowthatblockingjust1.8per centoftheincidentenergyinthesun’srayswouldcanceloutthewarming effectsproducedbyadoublingofgreenhousegasesintheatmosphere.Thatcould becrucialbecauseeventhemostsevereemissions-controlmeasuresbeing proposedwouldleaveuswithadoublingofcarbondioxidebytheendofthis centuryandthatwouldlastforatleastacentury more.Accordingtothefirsttwoparagraphstheauthorthinksthat
{{*HTML*}}下面有3篇短文每篇短文后有5道题请根据短文内容为每题确定1个最佳选项{{B}}第一篇{{/B}} ElectricBackpack? ?Backpacks背包areconvenient.Theycanholdyourbooksyourlunchanda changeofclothesleavingyourhandsfreetodootherthings.Somedayifyou don’tmindcarryingaheavyloadyourbackpacksmightalsopoweryourMP3 playerkeepyourcellphonerunningandmaybeevenlightyourway home.??LawrenceC.RomeandhiscolleaguesfromtheUniversityof PennsylvaniainPhiladelphiaandtheMarineBiologicalLaboratoryinWoodsHole Mass.haveinventedabackpackthatmakeselectricityfromenergyproduced whileitswearerwalks.Inmilitaryactionssearch-and-rescueoperationsand scientificfieldstudiespeoplerelyincreasinglyoncellphonesglobal positioningsystemGPSreceiversnight-vision夜视镜goggles护目镜another batterypowereddevicestogetaroundanddotheirwork.Thebackpack’s electricity-generatingfeaturecoulddramaticallyreducetheamounto{a wearer’sloadnowdevotedtosparebatteries备用电池reportRomeandhis colleaguesintheSept.9Science.??Thebackpack’s electricity-creatingpowersdependonspringsusedtohangaclothpackfromits metalframe.Theframesitsagainstthewearer’sbackandthewholepackmoves upandclownasthepersonwalks.Agearmechanismconvertsverticalmovementso{ thepacktorotarymotionsofanelectricalgeneratorproducingupto7.4 watts.??Unexpectedlytestsshowedthatwearersofthenew backpackaltertheirgaitsinresponsetothepack’soscillationssothatthey carryloadsmorecomfortablyandwithlesseffortthantheydoordinary backpacks.BecauseofthatsurprisingadvantageRomeplanstocommercialize bothelectricandnon-electricversionsofthebackpack.??The backpackcouldbeespeciallyusefulforsoldiersscientistsmountaineersand emergencyworkerswhotypicallycarryheavybackpacks.Fortherestof uspower-generatingbackpackscouldmakeitpossibletowalkplayvideogames watchTVandlistentomusicallatthesametime.Electricity-generatingpacks aren’tonthemarketyetbutifyoudogetoneeventuallyjust makesuretolookbothwaysbeforecrossingthestreet !Backpacksareconvenientbecause
{{*HTML*}}??阅读下面的短文文中有15处空白每处空白给出了4个选项请根据短文的内容从4个选项中选择1个最佳答案 {{B}}??????? ??????????? ??DriedFoods{{/B}}??Centuriesagomandiscoveredthat removingmoisture{{U}}?51?{{/U}}foodhelpedtopreserveitandthat theeasiestwaytodothiswastoexposethefoodtothesunandwind.In this{{U}}?52?{{/U}}theNorthAmericanIndiansproducedriedmeatand makeitintocakestheScandinaviansmake{{U}}?53?{{/U}}fishandthe Arabsmakedrieddates.??Allfoodscontain{{U}}?54 ?{{/U}}cabbageandotherleafvegetablescontainasmuchas93%water ?potatoesandotherrootvegetables80%leanmeat75%andfishanything from80%to60%depending{{U}}?55?{{/U}}howfattyitis.Ifthiswater is{{U}}?56?{{/U}}theactivityofthebacteriawhichcausesfoodto gobadisstopped.??Nowdaymostfoodsaredriedmechanically. Themostcommon{{U}}?57?{{/U}}ofsuchdryingistoputfoodin chambers.Thisistheusualmethodfordryingsuchthings{{U}}?58 ?{{/U}}vegetablesmincedmeatandfish.??Liquidssuchas milkcoffeeteasoupsandeggsmaybedried{{U}}?59?{{/U}}pouring themoveraheatedhorizontalsteelcylinderorbysprayingthemintoachamber through{{U}}?60?{{/U}}acurrentofhotairpasses.Inthefirst{{U}} ?61?{{/U}}thedriedmaterialisscrapedofftherollerasathin filmwhichisthenbrokenupintosmallpiecesthoughstillrelativelycoarse flakes.Inthesecondprocessitfallstothebottomofthechamberasafine powder.Where{{U}}?62?{{/U}}piecesofmeatandvegetablesare requiredasinsouptheingredientsaredriedseparatelyandthen mixed.??Driedfoodstakeuplessroomandweighless{{U}} ?63?{{/U}}thesamefoodpackedincanorfrozen?andthey are{{U}}?64?{{/U}}toclimbersexplorersandsoldiersinbattlewho havelittlestoragespace.Theyarealsopopularwithhousewives{{U}}?65 ?{{/U}}ittakessolittletimetocookthem.Usuallyitisjustamatterof replacingthedried-outmoisturewithboiling water.
{{*HTML*}}下面有3篇短文每篇短文后有5道题请根据短文内容为每题确定1个最佳选项{{B}}第一篇{{/B}} ElectricBackpack? ?Backpacks背包areconvenient.Theycanholdyourbooksyourlunchanda changeofclothesleavingyourhandsfreetodootherthings.Somedayifyou don’tmindcarryingaheavyloadyourbackpacksmightalsopoweryourMP3 playerkeepyourcellphonerunningandmaybeevenlightyourway home.??LawrenceC.RomeandhiscolleaguesfromtheUniversityof PennsylvaniainPhiladelphiaandtheMarineBiologicalLaboratoryinWoodsHole Mass.haveinventedabackpackthatmakeselectricityfromenergyproduced whileitswearerwalks.Inmilitaryactionssearch-and-rescueoperationsand scientificfieldstudiespeoplerelyincreasinglyoncellphonesglobal positioningsystemGPSreceiversnight-vision夜视镜goggles护目镜another batterypowereddevicestogetaroundanddotheirwork.Thebackpack’s electricity-generatingfeaturecoulddramaticallyreducetheamounto{a wearer’sloadnowdevotedtosparebatteries备用电池reportRomeandhis colleaguesintheSept.9Science.??Thebackpack’s electricity-creatingpowersdependonspringsusedtohangaclothpackfromits metalframe.Theframesitsagainstthewearer’sbackandthewholepackmoves upandclownasthepersonwalks.Agearmechanismconvertsverticalmovementso{ thepacktorotarymotionsofanelectricalgeneratorproducingupto7.4 watts.??Unexpectedlytestsshowedthatwearersofthenew backpackaltertheirgaitsinresponsetothepack’soscillationssothatthey carryloadsmorecomfortablyandwithlesseffortthantheydoordinary backpacks.BecauseofthatsurprisingadvantageRomeplanstocommercialize bothelectricandnon-electricversionsofthebackpack.??The backpackcouldbeespeciallyusefulforsoldiersscientistsmountaineersand emergencyworkerswhotypicallycarryheavybackpacks.Fortherestof uspower-generatingbackpackscouldmakeitpossibletowalkplayvideogames watchTVandlistentomusicallatthesametime.Electricity-generatingpacks aren’tonthemarketyetbutifyoudogetoneeventuallyjust makesuretolookbothwaysbeforecrossingthestreet !Whatisimpliedinifyoudogetoneeventuallyjustmakesuretotookbothwaysbeforecrossingthestreet!?
{{*HTML*}}??A.fallasleepagain.??B.becomemoreenergetic thefollowingday??C.sleeplessthan7hours??D. confirmthoseseriousconsequences??E.suffersleep problems??F.sleepmorethan8hoursTogetagoodnight’srestpeoplemaynotneedto______.
{{*HTML*}}下面有3篇短文每篇短文后有5道题请根据短文内容为每题确定1个最佳选项{{B}}第一篇{{/B}} ElectricBackpack? ?Backpacks背包areconvenient.Theycanholdyourbooksyourlunchanda changeofclothesleavingyourhandsfreetodootherthings.Somedayifyou don’tmindcarryingaheavyloadyourbackpacksmightalsopoweryourMP3 playerkeepyourcellphonerunningandmaybeevenlightyourway home.??LawrenceC.RomeandhiscolleaguesfromtheUniversityof PennsylvaniainPhiladelphiaandtheMarineBiologicalLaboratoryinWoodsHole Mass.haveinventedabackpackthatmakeselectricityfromenergyproduced whileitswearerwalks.Inmilitaryactionssearch-and-rescueoperationsand scientificfieldstudiespeoplerelyincreasinglyoncellphonesglobal positioningsystemGPSreceiversnight-vision夜视镜goggles护目镜another batterypowereddevicestogetaroundanddotheirwork.Thebackpack’s electricity-generatingfeaturecoulddramaticallyreducetheamounto{a wearer’sloadnowdevotedtosparebatteries备用电池reportRomeandhis colleaguesintheSept.9Science.??Thebackpack’s electricity-creatingpowersdependonspringsusedtohangaclothpackfromits metalframe.Theframesitsagainstthewearer’sbackandthewholepackmoves upandclownasthepersonwalks.Agearmechanismconvertsverticalmovementso{ thepacktorotarymotionsofanelectricalgeneratorproducingupto7.4 watts.??Unexpectedlytestsshowedthatwearersofthenew backpackaltertheirgaitsinresponsetothepack’soscillationssothatthey carryloadsmorecomfortablyandwithlesseffortthantheydoordinary backpacks.BecauseofthatsurprisingadvantageRomeplanstocommercialize bothelectricandnon-electricversionsofthebackpack.??The backpackcouldbeespeciallyusefulforsoldiersscientistsmountaineersand emergencyworkerswhotypicallycarryheavybackpacks.Fortherestof uspower-generatingbackpackscouldmakeitpossibletowalkplayvideogames watchTVandlistentomusicallatthesametime.Electricity-generatingpacks aren’tonthemarketyetbutifyoudogetoneeventuallyjust makesuretolookbothwaysbeforecrossingthestreet !ThewordspringsinParagraph3means
Thechairman{{U}}proposed{{/U}}thatweshouldstopthemeeting.
{{*HTML*}}{{B}}第二篇{{/B}} FlyingtheHypertSkies? ?Alittleairplanehasgivennewmeaningtothetermgoinghyper. ??TheHyper-Xrecentlybroketherecordforair-breathingjet planeswhenittraveledatahypersonicspeedofseventimesthespeedofsound. That’sabout5000milesperhour.Atthisspeedyou’dgetaroundtheworld-- flyingalongtheequator赤道--inlessthan5hours.??The Hyper-Xisanunmannedexperimentalaircraftjust12feetlong.Itachieves hypersonic超音速的speedusingaspecialsortofengineknownasascramjet.It maysoundlikesomethingfromacomicbookbutengineershavebeenexperimenting withscramjetssincethe1960s.??Foranenginetoburnfueland produceenergyitneedsoxygen.Ajetenginelikethoseonpassenger airplanesgetsoxygenfromtheair.Arocketenginetypicallygoesfasterbut hastocarryitsownsupplyofoxygen.Ascramjet紧急刹车enginegoesasfastas arocketbutitdoesn’thavetocarryitsownoxygensupply.Ascramjet’s specialdesignallowsittoobtainoxygenfromtheairthatflowsthroughthe engine.Anditdoessowithoutlettingthefast-movingairputoutthe combustion燃烧flames.Howeverascramjetengineworksproperlyonlyatspeeds greaterthanfivetimesthespeedofsound.AboosterrocketcarriedtheHyper-X toanaltitudeofabout100000feetforitstestflight.Theaircraft’s record-beatingflightlastedjust11seconds.Althoughthelittleplane’s self-poweredflightlastedonly11secondsthatbriefjourneyonMarch27makes amajormilestoneonthewaytoanewbreedofveryfastairplanescomments WernerJ.A.DahmoftheUniversityofMichiganinAnnArbor.Inthefuture engineerspredictairplanesequippedwithscramjetenginescouldtransport cargoquicklyandcheaplytothebrinkofspace.Suchhypersonicjetscould potentiallycarrypassengersanywhereintheworldinjustafew hours.??OutofthethreeexperimentalHyper-Xaircraftsbuiltfor NASAonlyoneisnowleft.Theagencyhasplansforanother11-second hypersonicflightthistimeat10timesthespeedofthe sound.WhatdidWernerJ.A.DahmoftheUniversityofMichigansayabouttheHyper-Xtestflight?
AboutonemillionAmericansarediagnosed{{U}}annually{{/U}}withskincancer.
{{*HTML*}}下面的短文后列出了7个句子请根据短文的内容对每个句子做出判断如果该句提的是正确信息请选择A如果该句提的是错误信息请选择B如果该句的信息文中没有提及请选择C ComputerMouse??The basiccomputermouseisanamazinglycleverinventionwitharelativelysimple designthatallowsustopointatthingsonthecomputeranditisvery productive.Thinkofallthethingsyoucandowithamouselikeselectingtext forcopyingandpasting涂drawingandevenscrollingonthepagewiththe newermicewiththewheel.Mostofususethecomputermousedailywithout stoppingtothinkhowitworksuntilitgetsdirtyandwehavetolearnhowto cleanit.Welearntopointatthingsbeforewelearntospeaksothemouseis averynaturalpointingdevice.?Othercomputerpointingdevicesinclude lightpensgraphics图形tabletsandtouchscreensbutthemouseisstillour workhorse.??Thecomputermousewasinventedin1964byDouglas EnglehartofStanfordUniversity.Ascomputerscreensbecamemorepopularand arrowkeyswereusedtomovearoundabodyoftextitbecameclearthata pointingdevicethatallowedeasiermotionthroughthetextandevenselection oftextwouldbeveryuseful.TheintroductionofthemousewiththeAppleLisa computerin1983reallystartedthecomputerpublicontheroadtorelyingon themouseforroutine常规computertasks.??Howdoesthemouse work?Wehavetostartatthebottomsothinkupsidedownfornow.Itall startswiththemouseball.Asthemouseballinthebottomofthemouserolls overthemousepaditpressesagainstandturnstwoshafts轴.Theshaftsare conneectedtowheelswithseveralsmallholesinthem.Thewheelshaveapairof smallelectroniclight-emittingdevicescalledlight-emittingdiodesLED mountedoneitherside.OneLEDsendsalightbeamtotheLEDontheotherside. AsthewheelsspinandaholerotatesbythelightbeamgetsthroughtotheLED ontheotherside.Butamomentlaterthelightbeamisblockeduntilthenext holeisinplace.TheLEDdetects发现achangingpatternoflightconvertsthe patternintoanelectronicsignalandsendsthesignal发信号tothecomputer throughwiresinacablethatgoesoutthemousebody.Thiscableisthetail thathelpsgivethemouseitsname.Thecomputerinterpretsthesignaltotell itwheretopositionthecursoronthecomputerscreen.??Sofar wehaveonlydiscussedthebasiccomputermousethatmostofyouprobablyhave orhaveused.Oneproblemwiththisdesignisthatthemousegetsdirtyasthe ballrollsoverthesurfaceandpicksupdirt.Eventuallyyouhavetocleanyour mouse.Theneweropticalmiceavoidthisproblembyhavingnomoving parts.Accordingtotheauthorgeneralcomputerusersneednottoknowhowthecomputermousewasinvented.
{{U}}While{{/U}}wedon'tagreewecontinuetobefriends.
{{*HTML*}}{{B}}第三篇{{/B}} ASunshadeforthePlanet? ?Evenwiththebestwillintheworldreducingourcarbonemissionsisnot goingtopreventglobalwarming.Ithasbecomeclearthatevenifwetakethe moststrongmeasurestocontrolemissionstheuncertainties不确定inour climatemodelsstillleaveopenthepossibilityofextremewarmingandrisesin sealevel.Atthesametimeresistancebygovernmentsandspecialinterest groupsmakesitquitepossiblethattheactionssuggestedbyclimatescientists mightnotbeimplemented执行soonenough.??Fortunatelyifthe worstcomestotheworstscientistsstillhaveafewtricksuptheirsleeves. Forthemostparttheyhavestronglyresisteddiscussingtheseoptionsforfear ofinvitingasenseofcomplacencythatmightthwarteffortstotackletheroot oftheproblem.Untilnowthatis.Agrowingnumberofresearchersaretakinga freshlookatlarge-scalegeoengineeringprojectsthatmightbeusedto counteract抵消globalwarming.IusetheanalogyofmethadonesaysStephen SchneideraclimateresearcheratStanfordUniversityinCaliforniawhowas amongthefirsttodrawattentiontoglobalwarming.Ifyouhaveaheroin addictthecorrecttreatmentishospitalizationandalongrehaB.Butifthey absolutelyrefusemethadoneisbetterthanheroin.??Basically theideaistoapplysunscreentothewholeplanet.Oneastronomerhascomeup witharadicalplantocoolEarth;launchtrillionsoffeather-lightdiscsinto spacewheretheywouldformavastcloudthatwouldblockthesun’srays.It’s controversialbutrecentstudiessuggesttherearewaystodeflectjustenough ofthesunlightreachingtheEarth’ssurfacetocounteractthewarmingproduced bythegreenhouseeffect.Globalclimatemodelsshowthatblockingjust1.8per centoftheincidentenergyinthesun’srayswouldcanceloutthewarming effectsproducedbyadoublingofgreenhousegasesintheatmosphere.Thatcould becrucialbecauseeventhemostsevereemissions-controlmeasuresbeing proposedwouldleaveuswithadoublingofcarbondioxidebytheendofthis centuryandthatwouldlastforatleastacentury more.WhatisNOTtrueoftheeffectivenessofsunscreenaccordingtothelastparagraph?
{{*HTML*}}? ?下面的短文后有2项测试任务1第23～26题要求从所给的6个选项中为第3～6段每段选择1个最佳标题2第27～30题要求从所给的6个选项中为每个句子确定1个最佳选项? ? MoreThan8HoursSleepTooMuchofaGood Thing??Althoughthedangersoftoolittlesleep arewidelyknownnewresearchsuggeststhatpeoplewhosleeptoomuchmayalso suffertheconsequences.??InvestigatorsattheUniversityof CaliforniainSanDiegofoundthatpeoplewhoclockup9or10hourseach weeknightappeartohavemoretroublefallingandstayingasleepaswellasa numberofothersleepproblemsthanpeoplewhosleep8hoursanight.People whosleptonly7hourseachnightalsosaidtheyhadmoretroublefallingasleep andfeelingrefreshedafteranight’ssleepthan8-hoursleepers.? ?ThesefindingswhichDr.DanielKripkereportedinthejournal PsychosomaticMedicinedemonstratethatpeoplewhowanttogetagoodnight’s restmaynotneedtosetasidemorethan8hoursanight.Headdedthatit mightbeagoodideaforpeoplewhosleepmorethan8hourseachnightto considerreducingtheamountoftimetheyspendinbedbutcautionedthatmore researchisneededtoconfirmthis.??Previousstudieshaveshown thepotentialdangersofchronicshortagesofsleep--forinstanceonereport demonstratedthatpeoplewhohabituallysleeplessthan7hourseachnighthave ahigherriskofdyingwithinafixedperiodthanpeoplewhosleep more.??ForthecurrentreportKripkereviewedtheresponsesof 1004adultstosleepquestionnairesinwhichparticipantsindicatedhowmuch theysleptduringtheWeekandwhethertheyexperiencedanysleepproblems. Sleepproblemsincludedwakinginthemiddleofthenightarisingearlyinthe morningandbeingunabletofallbacktosleepandhavingfatigueinterfere withday-to-dayfunctioning.??Kripkefoundthatpeoplewhoslept between9and10hourseachnightweremorelikelytoreportexperiencingeach sleepproblemthanpeoplewhoslept8hours.InaninterviewKripkenotedthat longsleepersmaystruggletogetrestatnightsimplybecausetheyspendtoo muchtimeinbed.Asevidenceheaddedthatonewaytohelpinsomniaisto spendlesstimeinbed.Itstandstoreasonthatifapersonspendstoolonga timeinbedthenthey’llspendahigherpercentageoftimeawake.he said. ??A.Keprike’sResearchTool??B.Dangersof HabitualShortagesofSleep??C.CriticismonKripke’s Report??D.AwayofOvercomingInsomnia??E.Sleep ProblemsofLongandShortSleepers??F.ClassificationofSleen ProblemsParagraph5______
{{*HTML*}}??阅读下面的短文文中有15处空白每处空白给出了4个选项请根据短文的内容从4个选项中选择1个最佳答案 {{B}}??????? ??????????? ??DriedFoods{{/B}}??Centuriesagomandiscoveredthat removingmoisture{{U}}?51?{{/U}}foodhelpedtopreserveitandthat theeasiestwaytodothiswastoexposethefoodtothesunandwind.In this{{U}}?52?{{/U}}theNorthAmericanIndiansproducedriedmeatand makeitintocakestheScandinaviansmake{{U}}?53?{{/U}}fishandthe Arabsmakedrieddates.??Allfoodscontain{{U}}?54 ?{{/U}}cabbageandotherleafvegetablescontainasmuchas93%water ?potatoesandotherrootvegetables80%leanmeat75%andfishanything from80%to60%depending{{U}}?55?{{/U}}howfattyitis.Ifthiswater is{{U}}?56?{{/U}}theactivityofthebacteriawhichcausesfoodto gobadisstopped.??Nowdaymostfoodsaredriedmechanically. Themostcommon{{U}}?57?{{/U}}ofsuchdryingistoputfoodin chambers.Thisistheusualmethodfordryingsuchthings{{U}}?58 ?{{/U}}vegetablesmincedmeatandfish.??Liquidssuchas milkcoffeeteasoupsandeggsmaybedried{{U}}?59?{{/U}}pouring themoveraheatedhorizontalsteelcylinderorbysprayingthemintoachamber through{{U}}?60?{{/U}}acurrentofhotairpasses.Inthefirst{{U}} ?61?{{/U}}thedriedmaterialisscrapedofftherollerasathin filmwhichisthenbrokenupintosmallpiecesthoughstillrelativelycoarse flakes.Inthesecondprocessitfallstothebottomofthechamberasafine powder.Where{{U}}?62?{{/U}}piecesofmeatandvegetablesare requiredasinsouptheingredientsaredriedseparatelyandthen mixed.??Driedfoodstakeuplessroomandweighless{{U}} ?63?{{/U}}thesamefoodpackedincanorfrozen?andthey are{{U}}?64?{{/U}}toclimbersexplorersandsoldiersinbattlewho havelittlestoragespace.Theyarealsopopularwithhousewives{{U}}?65 ?{{/U}}ittakessolittletimetocookthem.Usuallyitisjustamatterof replacingthedried-outmoisturewithboiling water.
{{*HTML*}}{{B}}第二篇{{/B}} FlyingtheHypertSkies? ?Alittleairplanehasgivennewmeaningtothetermgoinghyper. ??TheHyper-Xrecentlybroketherecordforair-breathingjet planeswhenittraveledatahypersonicspeedofseventimesthespeedofsound. That’sabout5000milesperhour.Atthisspeedyou’dgetaroundtheworld-- flyingalongtheequator赤道--inlessthan5hours.??The Hyper-Xisanunmannedexperimentalaircraftjust12feetlong.Itachieves hypersonic超音速的speedusingaspecialsortofengineknownasascramjet.It maysoundlikesomethingfromacomicbookbutengineershavebeenexperimenting withscramjetssincethe1960s.??Foranenginetoburnfueland produceenergyitneedsoxygen.Ajetenginelikethoseonpassenger airplanesgetsoxygenfromtheair.Arocketenginetypicallygoesfasterbut hastocarryitsownsupplyofoxygen.Ascramjet紧急刹车enginegoesasfastas arocketbutitdoesn’thavetocarryitsownoxygensupply.Ascramjet’s specialdesignallowsittoobtainoxygenfromtheairthatflowsthroughthe engine.Anditdoessowithoutlettingthefast-movingairputoutthe combustion燃烧flames.Howeverascramjetengineworksproperlyonlyatspeeds greaterthanfivetimesthespeedofsound.AboosterrocketcarriedtheHyper-X toanaltitudeofabout100000feetforitstestflight.Theaircraft’s record-beatingflightlastedjust11seconds.Althoughthelittleplane’s self-poweredflightlastedonly11secondsthatbriefjourneyonMarch27makes amajormilestoneonthewaytoanewbreedofveryfastairplanescomments WernerJ.A.DahmoftheUniversityofMichiganinAnnArbor.Inthefuture engineerspredictairplanesequippedwithscramjetenginescouldtransport cargoquicklyandcheaplytothebrinkofspace.Suchhypersonicjetscould potentiallycarrypassengersanywhereintheworldinjustafew hours.??OutofthethreeexperimentalHyper-Xaircraftsbuiltfor NASAonlyoneisnowleft.Theagencyhasplansforanother11-second hypersonicflightthistimeat10timesthespeedofthe sound.WhatkindofanenginedidtheHyper-Xuse?
热门题库
更多
语文
中石油职称英语
理工类
卫生类
综合类
国际货运代理师
报关水平测试
报检员
物流员(四级)
助理物流师(三级)
物流师(二级)
高级物流师(一级)
物流案例分析
单证员基础理论与知识
单证员缮制与操作
国际货运代理理论与实务
湘公网安备 43130202000226号