2012年6月全国大学英语四级考试试题(二)

2012年6月全国大学英语四级考试试题（二）PartIWriting(30minutes)Directions:Forthispart,youareallowed30minutestowriteacompositiononthetopicShouldSmokingBeCompletelyBanned.Youshouldwriteatleast120wordsfollowingtheoutlinegivenbelowinChinese:1.有人赞同完全禁止吸烟，理由是……2.有人不赞同完全禁止吸烟，理由是……3.我的看法。ShouldSmokingBeCompletelyBannedPartIIReadingComprehension(SkimmingandScanning)(15minutes)Directions:Inthispart,youwillhave15minutestogooverthepassagequicklyandanswerthequestionsonAnswerSheet1.Forquestions1-7,choosethebestanswerfromthefourchoicesmarked[A],[B],[C]and[D].Forquestions8-10,completethesentenceswiththeinformationgiveninthepassage。SpaceOurFutureinSpace:ItHasAlreadyBegun!Weareallspacetravelers.Butwe’vestayedclosetohomeuntilnow.Oneday,wemayleaveour“mothership”Earthtomakeourhomeamongthestars。Agiant,spherical“spaceship”，about8,000milesindiameter,isspeedingthroughthesolarsystemrightnow.Itiscruisingatanincredible66,600milesperhour。It’snotagiant,StarWarsmothership.It’sspaceshipEarth,thehomeofoverfourbillionpeople.Thiswatercoatedspaceshiphasbeentravelingthroughtheuniverseforaboutfivebillionyears.Onlywithinthepast25years,however,havesomeofitspassengersbrokenfreeofEarth’sgravity。But25yearsfromnow,manypeople,includingyou,mightliveinanorbitingspacestation200milesabovetheEarth。SpaceCitiesScientistshavealreadydesignedspecialspacefactories.Thesefactorieswilltakeadvantageoftheabsenceofgravity(zerogravity)toproduceeverythingfromlife-savingdrugstoperfectballbearings。Otherscientistshavedesignedspacecolonies,completewithfarms,schools,andartificialdayandnight.Hundreds,oreventhousands,ofpeoplewilllive,work,play—evengotoschool,farabovetheEarth。Ourconquestofspace,ofcourse,hasalreadybegun.WehaveexploredpartoftheMoon,sentrobotspaceshipsontothesurfaceofVenusandMars,andaimedspaceprobespasttheplanetsofJupiterandSaturn。LastJune,onerobotship,Pioneer10,leftoursolarsystemforever.AndastronautsfromboththeSovietUnionandtheUnitedStateshavelivedinspacestations。Theconquestofspace,withoutquestion,isoneofthegreatestadventureshumanbeingshaveeversetouton.Butitmaybemorethanagreatadventure.Somescientiststhinktheconquestofspacemaybeanecessityforsurvivalofthehumanspecies。WearetearingupmoreandmoreoftheEarthtogetrawmaterialsforindustry.Andwearepollutingtheairandwateraswemanufactureproductsthatweneedorwant.Almosteverythingthatseemstomakeourlivesmorecomfortable,andfromelectricitytopesticides,usesuporaltersapieceofourplanet’snaturalenvironment。WhyGointoSpace?Yetoursolarsystemisfullofresources.Themoonischockfullofvaluablemetals.Soaretheasteroids,thesmall,rocky,planet-likebodiesorbitingthesunmostofthembetweenMarsandJupiter.Thesemetals,ifwecangetthem,couldbeusedtobuildfactoriesandspacestations.Also,inspace,thereisnoatmospheretofilteroutthesun’senergy.Thereisplentyofsolarenergytobeturnedintoelectricityformanufacturing,forcreatingcomfortablelivingconditions。GettingawayfromEarthhasotheradvantages,too.Modernindustryusesmanykindsofmetalalloys(mixturesofmetalthatarebetterforcertainpurposesthanpuremetals).Yetsomemetalalloyseithercan’tbemadeorareveryexpensivetomakeonEarthbecauseofgravity.Forinstance,certainmetalsdon’tmixwellonEarth.Butinzerogravity,molten(hot,liquid)metalsmixmoreevenly.Thisisbecausethereisnogravitytopulltheheaviermetalsdown,whilethelighteronesfloatontop。Fromspace,too,wecanlookdownontheEarthandstudytheatmosphere,itsweather,andtheeffectsofairpollution。Andbecausethereisnostronggravitytobreakfreefrom,ourfuturehomesawayfromEarthwillbeconvenientstartingpointsfortraveltodistantplanets。But,whilegoingintospacemightsolvesomeproblems,outerspacecanalsobeadangerousplace.Forexample,inouterspace,wehavetoprotectourselvesfromthedangersofultravioletlightandcosmicrays.UltravioletlightfromthesuncangiveusbadsunburnsrighthereonEarth.Yet,Earth’satmospherescreensoutmostofthatharmfulradiation.Cosmicraysaretinyhighenergyparticlesfromouterspace.Again,theEarthshieldsusfrommostofthem。AtHomeinSpace?Butinspace,withoutspecialprotection,wewouldbeexposedtomuchstrongerradiationfromultravioletlightandcosmicrays.Also,inthezerogravityofouterspace,ourboneswilllosecalciumandbecomeweaker.Thiswillbemoreofaproblemthelongerpeoplestayoutinspace.Doctorsarelookingforawaytokeepourbonesfromlosingcalciuminouterspace.Andasmallspaceshipjustmight“driveyoubatty”afterawhile.Butevenonashorttripinouterspace,youmightnotfeelaswellasyou’dliketo.Spacetravelcouldmakeyouseasick!Yet,theseriskswon’tkeeppeoplefromgoingintospace.Eventually,anEarth-likeenvironmentwillbebuiltinspace.Andtheywillbepopulatedbypeoplewithmanydifferentinterests:medicine,construction,farming,teaching,mining,andsoon。Thenexthundredyearswillbefilledwithotherworldlyadventures,excitingscientificdiscoveries,anddanger,ashumansleaveEarth—perhapsforever。AginginSpaceSupposeaspacetravelerismovingatavelocityof186,200milespersecond.Foreveryhourthatpassesforhim,30hourspassonEarth.Ifhetravelsforayearinthisfashion(havingacceleratedinstantaneously)andthenturnsaroundandcomesbackatthisspeed(havingturnedaroundinstantaneously)，hewillfindthatwhilehehasseemedtohimselftohavetraveledtwoyears,themenonE