大学英语六级综合模拟题阅读.docx

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