大学英语四级模拟试卷二及参考答案

句典翻译机单词不用背(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’sgravityBut25yearsfromnow,manypeople,includingyou,mightliveinanorbitingspacestation200milesabovetheEarth.SpaceCities句典翻译机单词不用背(zerogravity)toproduceeverythingfromlifesavingdrugstoperfectballbearings.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,planetlikebodiesorbitingthesunmostofthembetweenMarsandJupiter.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.句典翻译机单词不用背’satmospherescreensoutmostofthatharmfulradiation.Cosmicraysaretinyhighenergyparticlesfromouterspace.Again,theEarthshieldsusfrommostofthem.AtHomeinSpace?Butinspace,withoutspecialprotection,wewouldbeexposedtomuchstrongerradiationfromultravioletlightandcosmicrays.Also,inthezerogravityofouterspace,ourboneswilllosecalciumandbecomeweaker.Thiswillbemoreofaproblemthelongerpeoplestayoutinspace.Doctorsarelookingforawaytokeepourbonesfromlosingcalciuminouterspace.Andasmallspaceshipjustmight“driveyoubatty”afterawhile.Butevenonashorttripinouterspace,youmightnotfeelaswellasyou’dliketo.Spacetravelcouldmakeyouseasick!Yet,theseriskswon’tkeeppeoplefromgoingintospace.Eventually,anEarthlikeenvironmentwillbebuiltinspace.Andtheywillbepopulatedbypeoplewithmanydifferentinterests:medicine,construction,farming,teaching,mining,andsoon.Thenexthundredyearswillbefilledwithotherworldlyadventures,excitingscientificdiscoveries,anddanger,ashumansleaveEarth—perhapsforever.AginginSpaceSupposeaspacetravelerismovingatavelocityof186,200milespersecond.Forevery