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7SupposewebuiltarobottoexploretheplanetMars.Weprovidetherobotwithseeingdetectors(探测器)tokeepitawayfromdanger.Itispoweredentirelybythesun.Shouldweprogramtherobottobeequallyactiveatallthetimes?No.Therobotwouldbeusingupenergyatatimewhenitwasnotreceivingany.Sowewouldprobablyprogramittostopitsactivityatnightandtomakeupatdawnthenextmorning.Accordingtotheevolutionary(进化的)theoryofsleep,evolutionaryequippeduswitharegularpatternofsleepingandwalkingforthesamereason.Theorydoesnotdeny(否认)Thatsleepprovidessomeimportantrestorativefunctions(恢复功能).Itmerelysaysthatevolutionaryhasprogrammedustoperformthosefunctionsatatimewhenactivitywouldbeinefficient(无效的)andpossiblydangerious.However,sleepprotectsusonlyfromthesortoftroublewemightwalkinto;itdoesnotprotectusfromtroublethatcomeslookingforus.Sowesleepwellwhenweareinafamiliar,safeplace,butwesleeplightly,ifatall,whenwefearthatbearswillnoseintothetent.Theevolutionarytheoryexplainsthedifferencesinsleepamongcreatures.Whydocats,forexample,sleepsomuch,whilehorsessleepsolittle?Surelycatsdonotneedfivetimesasmuchrepairandrestorationashorsedo.Butcatscanaffordtohavelongperiodsofinactivitybecausetheyspendlittletimeeatingandareunlikelytobeattackedwhiletheysleep.Horsemustspendover,theycannotaffordtosleeptolongortoodeeply,becausetheirsurvival(生存)dependsontheirabilitytorunawayfromattackers.1.Theauthorusestheexampleoftherobotinspaceexplorationtotellus______.A.thedifferencesbetweenrobotsandmenB.thereasonwhymenneedtosleepC.aboutthemeedforrobotstosavepowerD.aboutthedangerofmenworkingatnight2.Evolutionhasprogrammedmantosleepatnightchieflytohelphim______.A.keepuparegularpatternoflifeB.preventtroublethatcomeslookingforhimC.avoiddangerandinefficientlabourD.restorehisbodilyfunctions3.Accordingtotheauthor,wecannotsleepwellwhenwe_______.A.areworryingaboutoursafetyB.areoverworkedC.areinatentD.areawayfromhome4.Catssleepmuchmorethanhorsesdopartlybecausecats_____________.A.needmoretimeforrestorationB.areunlikelytobeattackersC.aremoreactivethanhorseswhentheyareawakeD.spendlesstimeeatingtogetenoughenergy5.Whichofthefollowingisthemainideaofthepassage?A.EvolutionhasequippedallcreatureswitharegularpatternofsleepingandwakingB.ThestudyofthesleepisanimportantpartoftheevolutionarytheoryC.SleepingpatternmustbetakenintoconsiderationinthedesigningoftherobotD.Thesleepingpatternofalivingcreatureisdeterminedbythefooditeats