大学英语六级综合模拟题阅读Word文档下载推荐.docx
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大学英语六级综合模拟题阅读Word文档下载推荐.docx
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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
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