大学英语六级综合模拟题阅读.docx
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大学英语六级综合模拟题阅读
大学英语六级综合模拟题阅读
PassageOne
Earthquakes
Anearthquakeisoneofthemostterrifyingphenomenathatnaturecandishup.Wegenerallythinkofthegroundwestandonas "rock-solid"andcompletelystable.Anearthquakecanshatter(粉碎)thatperceptioninstantly,andoftenwithextremeviolence.
Upuntilrelativelyrecently,scientistsonlyhadunsubstantiated(无确实证据的)guessesastowhatactuallycausedearthquakes.Eventodaythereisstillacertainamountofmysterysurroundingthem,butscientistshaveamuchclearerunderstanding.
Therehasbeenenormousprogressinthepastcentury:
Scientistshaveidentifiedtheforcesthatcauseearthquakes,anddevelopedtechnologythatcantellusanearthquake'smagnitudeandorigin.Thenexthurdleistofindawayofpredictingearthquakes,sotheydon'tcatchpeoplebysurprise.
Inthisarticle,we'llfindoutwhatcausesearthquakes,andwe'llalsofindoutwhytheycanhavesuchadevastatingeffectonus.
ShakingGround
Anearthquakeisavibration(震动)thattravelsthroughtheearth'scrust.Technically,alargetruckthatrumblesdownthestreetiscausingamini-earthquake,ifyoufeelyourhouseshakingasitgoesby;butwetendtothinkofearthquakesaseventsthataffectafairlylargearea,suchasanentirecity.Allkindsofthingscancauseearthquakes:
·volcaniceruptions
·meteorimpacts
·undergroundexplosions(anundergroundnucleartest,forexample)
·collapsingstructures(suchasacollapsingmine)
·Butthemajorityofnaturally-occurringearthquakesarecausedbymovementsoftheearth'splates.
·Weonlyhearaboutearthquakesinthenewseveryonceinawhile,buttheyareactuallyaneverydayoccurrenceonourplanet.AccordingtotheUnitedStatesGeologicalSurvey,morethan3millionearthquakesoccureveryyear.That'sabout8,000aday,oroneevery11seconds!
Thevastmajorityofthese3millionquakesareextremelyweak.Thelawofprobabilityalsocausesagoodnumberofstrongerquakestohappeninuninhabitedplaceswherenoonefeelsthem.Itisthebigquakesthatoccurinhighlypopulatedareasthatgetourattention.
Earthquakeshavecausedagreatdealofpropertydamageovertheyears,andtheyhaveclaimedmanylives.Inthelasthundredyearsalone,therehavebeenmorethan1.5millionearthquake-relatedfatalities.Usually,it'snottheshakinggrounditselfthatclaimslives;it'stheassociateddestructionofmanmadestructuresandtheinstigation(发起)ofothernaturaldisasters,suchastsunamis,avalanches(雪崩)andlandslides.SlidingPlates
Thebiggestscientificbreakthroughinthehistoryofseismology--thestudyofearthquakes--cameinthemiddleofthe20thcentury,withthedevelopmentofthetheoryofplatetectonics(筑造学).Scientistsproposedtheideaofplatetectonicstoexplainanumberofpeculiarphenomenaonearth,suchastheapparentmovementofcontinentsovertime,theclusteringofvolcanicactivityincertainareasandthepresenceofhugeridgesatthebottomoftheocean.
Thebasictheoryisthatthesurfacelayeroftheearth--thelithosphere--iscomprisedofmanyplatesthatslideoverthelubricating(润滑的)athenospherelayer.Attheboundariesbetweenthesehugeplatesofsoilandrock,threedifferentthingscanhappen:
·Platescanmoveapart.Iftwoplatesaremovingapartfromeachother,hot,moltenrockflowsupfromthelayersofmantlebelowthelithosphere.Thismagma(岩浆)comesoutonthesurface(mostlyatthebottomoftheocean),whereitiscalledlava(熔岩).Asthelavacools,ithardenstoformnewlithospherematerial,fillinginthegap.Thisiscalledadivergentplateboundary.
·Platescanpushtogether.Ifthetwoplatesaremovingtowardeachother,oneplatetypicallypushesundertheotherone.Thissub-ductingplatesinksintothelowermantlelayers,whereitmelts.Atsomeboundarieswheretwoplatesmeet,neitherplateisinapositiontosub-ductundertheother,sotheybothpushagainsteachothertoformmountains.Thelineswhereplatespushtowardeachotherarecalledconvergentplateboundaries.
·Platesslideagainsteachother.Atotherboundaries,platessimplyslidebyeachother--onemovesnorthandonemovessouth,forexample.Whiletheplatesdon'tdriftdirectlyintoeachotheratthesetransformboundaries,theyarepushedtightlytogether.Agreatdealoftensionbuildsattheboundary.
DealingwithEarthquakes
Weunderstandearthquakesalotbetterthanwedideven50yearsago,butwestillcan'tdomuchaboutthem.Theyarecausedbyfundamental,powerfulgeologicalprocessesthatarefarbeyondourcontrol.Theseprocessesarealsofairlyunpredictable,soit'snotpossibleatthistimetotellpeopleexactlywhenanearthquakeisgoingtooccur.Thefirstdetectedseismicwaveswilltellusthatmorepowerfulvibrationsareontheirway,butthisonlygivesusafewminutes'warning,atmost.
Sowhatcanwedoaboutearthquakes?
Themajoradvancesoverthepast50yearshavebeeninpreparedness,particularlyinthefieldofconstructionengineering.In1973,theUniformBuildingCode,aninternationalsetofstandardsforbuildingconstruction,addedspecificationstofortifybuildingsagainsttheforceofseismicwaves.Thisincludesstrengtheningsupportmaterialaswellasdesigningbuildingssotheyareflexibleenoughtoabsorbvibrationswithoutfallingordeteriorating.It'sveryimportanttodesignstructuresthatcantakethissortofpunch,particularlyinearthquake-proneareas.
Anothercomponentofpreparednessiseducatingthepublic.TheUnitedStatesGeologicalSurvey (USGS)andothergovernmentagencieshaveproducedseveralbrochuresexplainingtheprocessesinvolvedinanearthquakeandgivinginstructionsonhowtoprepareyourhouseforapossibleearthquake,aswellaswhattodowhenaquakehits.
Inthefuture,improvementsinpredictionandpreparednessshouldfurtherminimizethelossoflifeandpropertyassociatedwithearthquakes.Butitwillbealongtime,ifever,beforewe'llbereadyforeverysubstantialearthquakethatmightoccur.Justlikesevereweatheranddisease,earthquakesareanunavoidableforcegeneratedbythepowerfulnaturalprocessesthatshapeourplanet.Allwecandoisincreaseourunderstandingofthephenomenonanddevelopbetterwaystodealwithit.
1、Scientistshadunsubstantiatedguessesasto______upuntilrelativelyrecently.
A.whenactuallyearthquakeshappened
B.whatactuallycausedearthquakes
C.howearthquakeshappened
D.whereactuallyearthquakeshappened
2、Whatisanearthquake?
A.Anearthquakeisthemostterrifyingphenomenathatnaturecanpresenttohumanbeings.
B.Anearthquakecanshatterourworldinstantly,andoftenwithextremeviolence.
C.Anearthquakeisavibrationthattravelsthroughtheearth'score.
D.Anearthquakeisavibrationthattravelsthroughtheearth'scrust.
3、Themajorityofnaturally-occurringearthquakesarecausedby______.
A.volcaniceruptions
B.meteorimpacts
C.collapsingstructures
D.movementsoftheearth'splates
4、HowmanyearthquakesoccureverydayaccordingtotheUnitedStatesGeologicalSurvey?
A.Morethan3million.
B.1.5million.
C.About8,000.
D.11.
5、 Scientistsproposedtheideaofplatetectonicstoexplain______.
A.anumberofpeculiarphenomenaonearth
B.anumberofregularphenomenaonearth
C.theclusteringofvolcanicactivityinuncertainareas
D.thepresenceofhugeridgesatthetopoftheocean
6、 Thesurfacelayeroftheearthisthelithosphere,whichiscomprisedofmanyplatesthatslideover______.
A.thepresenceofhugeridges
B.thelubricatingathenospherelayer
C.thenewlithospherematerial
D.theclusteringofvolcanicactivity
7、 Whatwillhappeniftwoplatesaremovingapartfromeachother?
A.Oneplatetypicallypullstheotherone.
B.Oneplatetypicallypushesundertheotherone.
C.Theconvergentplateboundarieswillbeformed.
D.Hot,moltenrockflowsupfromthelayersofmantlebelowthelithosphere.
8、Theconvergentplateboundariesrefertothelineswhereplates______.
9、Themajoradvancesoverthepast50yearshavebeeninpreparedness,particularlyinthefieldofconstructionengineeringand______.
10、Inthefuture,improvementsinpredictionandpreparednessshouldfurtherminimizethelossof______associatedwithearthquakes.
PassageTwo
HowOzonePollutionWorks
IntroductiontoHowOzonePollutionWorks
TheweatherreportontheradioorTVtellsyouthatitisgoingtobesunnyandhotandthatanorangeozonealerthasbeenissued.Whatisozone?
Whatdoesanorangealertmean?
Whyshouldyoubeconcernedaboutit?
Inthisarticle,wewillexaminewhatozoneis,howitisproduced,whathealthhazardsitposesandwhatyoucandotoreduceozonepollution.
Ozoneisamoleculeofthreeoxygenatomsboundtogether(O3).Itisunstableandhighlyreactive.Ozoneisusedasableach,adeodorizingagent,andasterilizationagentforairanddrinkingwater.Atlowconcentrations,itistoxic.
Ozoneisfoundnaturallyinsmallconcentrationsinthestratosphere,alayerofEarth'supperatmosphere.Inthisupperatmosphere,ozoneismadewhenultravioletlightfromthesunsplitsanoxygenmolecule(O2),formingtwosingleoxygenatoms.Ifafreedatomcollideswithanoxogenmolecule,itbecomesozone.Stratosphericozonehasbeencalled "good"ozonebecauseitprotectstheEarth'ssurfacefromdangerousultravioletlight.
Ozonecanalsobefoundinthetroposphere,thelowestlayeroftheatmosphere.Troposphericozone(oftentermed"bad"ozone)isman-m