专题限时训练(三十七)[科普知识型阅读理解(一)](限时：25分钟)(一)Trafficlightsarekeytoolsforregulatingtrafficnow.Theyarenot,however,perfect.Driversexchangethetrafficjamsthatwouldhappenatunmanagedcrossingsforapatternofstopgomovementthatcanstillbeannoying,andwhichburnsmorefuelthanasmoothpassagewould.Creatingsuchasmoothpassagemeansadjustingavehicle'sspeedsothatitalwaysarrivesatthelightswhentheyaregreen.Thatistheoreticallypossible,butpracticallyhard.Roadsidesignswiredtotrafficlightscanhelpgetthemessageacrossacouplehundredmetresfromacrossing,butsuchsignsareexpensive,andarenotwidespread.MargaretMartonosiandEmmanouilKoukoumidisatPrincetonUniversity,andLiShiuanPehattheMassachusettsInstituteofTechnology,however,haveanideathatcouldmaketheprocesscheaperandmoreeffective.Insteadofahardwirednetworkofsigns,theyproposetousemobile-phoneapplications.Foradrivertobenefit,hemustloadtheteam'ssoftware,namedSignalGuru,intohisphoneandthenputitonaspecialthingattachedtotheinsideofhiscar'swindscreen,withthecameralens(镜头)pointingforward.SignalGuruisdesignedtodetecttrafficlightsandtracktheirstatusasred,yelloworgreen.Itbroadcaststhisinformationtootherphonesintheareathatarefittedwiththesamesoftware,and—ifthereareenoughofthem,thephonesthuseachknowthestatusofmostofthelightsaroundtown.Usingthisinformation,SignalGuruisabletocalculatethetrafficlightschedulefortheareaandsuggestthespeedatwhichadrivershouldtravelinordertoavoidredlights.TestsinCambridge,Massachusetts,wherefivedriverswereaskedtofollowthesamerouteforthreehours,andinSingapore,whereeightdriverswereaskedtofollowoneoftworoutesfor30minutes,revealedthatSignalGuruwascapableofpredictingtrafficlightactivitywithanaccuracyof98.2%and96.3%respectively,inthetwocities.ThiswasparticularlyimpressivebecauseinCambridgethelightsshifted,roughlyhalfwaythroughthetest,fromtheirunbusyscheduletotheirafternoontrafficschedule,whileinSingaporelightsareadaptive,usingdetectorsfixedundertheroadtodeterminehowmuchtrafficispresentandthuswhenasignalshouldchange.InneithercasewasSignalGurufooled.Fuelconsumptionfell,too—byabout20%.SignalGuruthusreducesbothannoyanceandfueluse,andmakesgoingbackandforthtoworkaslightlylesshorribleexperience.1．Roadsidesignswiredtotrafficlightsarenotthebestwaytocreateasmoothpassagebecause________，A．theyareexpensiveandeasilybreakB．theyaretoocostlyandnotwidelyusedC．theyarecomplexandconfusingtodriversD．theyaretheoreticallypossiblebutpracticallyuseless2．SignalGuruisanapplicationusedon________.A．acameraB．acomputerC．amobilephoneD．aGPSsysteminone'scar3．Withtheinformationitcollectsandprocesses,SignalGuruisableto________.A．helpdriversavoidtrafficaccidentsB．allowdriverstoadjusttheirspeedC．changethetrafficlightsinadvanceD．sendinformationtoallcellphones4．ThetestsinCambridgeandSingaporewereimpressivebecauseSignalGuru________.A．provedtobeunreliableB．operatedatahighspeedC．functionedratherstablyD．understooddrivers'schedules(二)Haveyoueverwonderedwhystems(茎)growupwardsandrootsdownwards?Whyplantsalwaysseemtoturntowardsthelightandclimbingplantsrunupratherthandown?Theanswerissimple:auxin(生长素),achemicalsubstancethatcontrolsgrowthinplants.AuxingivesawayitssecretsAuxinisaplanthormone(激素).Darwinwasalreadyinterestedinitinthe19thcentury.Onlyinrecentyears,however,hasthehormonestartedtogiveawayitssecrets,thankstointensivemolecularresearch.Auxinisproducedin...
