大学英语四级试题Word文档下载推荐.docx

大学英语四级试题Word文档下载推荐.docx

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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.我看法。

　　ShouldSmokingBeCompletelyBanned

　　PartIIReadingComprehension（SkimmingandScanning）

　　（15minutes）

　　Directions：

Inthispart，youwillhave15minutestogooverthepassagequicklyandanswerthequestionsonAnswerSheet1.

　　Forquestions1-7，mark

　　Y（forYES）ifthestatementagreeswiththeinformationgiveninthepassage;

　　N（forNO）ifthestatementcontradictstheinformationgiveninthepassage;

　　NG（forNOTGIVEN）iftheinformationisnotgiveninthepassage.

　　Forquestions8-10，completethesentenceswiththeinformationgiveninthepassage.

　　Space

　　OurFutureinSpace：

ItHasAlreadyBegun!

　　Weareallspacetravelers.Butwe’vestayedclosetohomeuntilnow.Oneday，wemayleaveour“mothership”Earthtomakeourhomeamongthestars.

　　Agiant，spherical“spaceship”，about8,000milesindiameter，isspeedingthroughthesolarsystemrightnow.Itiscruisingatanincredible66,600milesperhour.

　　It’snotagiant，StarWarsmother-ship.It’sspaceshipEarth，thehomeofoverfourbillionpeople.Thiswatercoatedspaceshiphasbeentravelingthroughtheuniverseforaboutfivebillionyears.Onlywithinthepast25years，however，havesomeofitspassengersbrokenfreeofEarth’sgravity.

　　But25yearsfromnow，manypeople，includingyou，mightliveinanorbitingspacestation200milesabovetheEarth.

　　SpaceCities

　　Scientistshavealreadydesignedspecialspacefactories.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，inthezerogravityofouters