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阅读D篇(1)Youhavelearnedaboutenergy.DoyouknowthatHEATisaformofENERGY?Yep,thisformofenergyactsoneverything.And,we’regoingtolookatafewexperimentstolearnhowthisformofenergyactsandwhyweneedtoknowallaboutit.Theheatenergyofsomethingisdecidedbyhowactiveitsatoms(原子)andmolecules(分子)are.Ahotobjectisonewhoseatomsandmoleculesareexcitedandshowrapidmovement.Acoolerobject’smoleculesandatomswillbelessexcitedandshowlessmovement.Whentheseguysareintheexcitedstate,theytakeupalotofspacebecausethey’removingaroundsofast.Whentheatomsandmoleculessettledown,orcooldown,theytakeuplessspace.IfaHOThigh-energyatomcomesintocontactwithacoollow-energyatom,theexcitedatomwillloosesomeofitsenergytothecoolatom.Thetwoatomswillreachanenergylevelthat’sbetweenwheretheyeachstartedout.ThatleveliscalledThermalEquilibrium.Experiment:Ifyouhaveacupofreallyhotchocolateandwanttocoolitdown,youmayputanicecubeinthecup.Aftertheicehascompletelymelted(disappeared),thehotchocolateandthemeltedicehavecometoThermalEquilibrium.Nowthatyouhaveanideaofwhatheatis,let’slookatsomeoftheeffectsofthisformofenergy.Here’sanotherexperiment.Blowupaballoon,butnotalltheway.Puttheballooninarefrigeratorforaboutanhour,thentakeitout.Diditbecomesmaller?Why?Itbecamesmallerbecausetheairmoleculesinsidetheballoonsloweddownandaretakinguplessspace.Nowputtheballoonindirectsunlight.Whathappenedafteritwarmedup?Why?Fromtheaboveexperiment,welearnedaveryimportantfact—heatcausesthingsto“grow”.WecallthisThermalExpansion.Ifthings“grow”whenheated,whatdoyouthinkhappenstothemwhentheygetcold?Ifyougetachancetocheckoutsomerailroadtracks,noticethegapsorseparationsbetweentherails.(Don’tgetrunoverbyatrain!)Thermalexpansionandcontractioniswhythosegapsareplacedtherethatway,andwhyexpansionjointsareplacedinlonghighwaybridges.You’veprobablyfeltexpansionjointsonoldconcretehighways.Rememberthe“thump–thump”soundasyourodeoverthem?57.Howmanyexperimentsarementionedinthepassage?A.Two.B.Three.C.Four.D.Five.58.WhatisThermalEquilibrium?A.Thefactthathotatomsloosesomeenergytocoolatomswhentheymeet.B.Thefactthattherearealwaysthegapsorseparationsbetweentherails.C.Thefactthatheatcausesthingstoincreaseinsize.D.Thefactthatheatisanotherformofenergy.59.Whyisthefirstparagraphwritten?A.Toexplainwhatheatenergyis.B.Tosortenergyformsforreaders.C.Togiveexamplesofheatenergy.D.Totellreaderswhattoreadhere.60.Whatisthelastparagraphmainlyabout?A.Whythermalexpansionisonthetracksandhighways.B.Howtocheckrailroadtracksandconcretehighways.C.Whyrailroadsandhighwaysarebuiltthatway.D.Howtorememberthe“thump–thump”sound.(2)Fightingfireshasalwaysbeenadangerousjob.Thejobhasgrownevenmoreriskyinrecentyears.That’sbecausechangesinbuildingoverthelast30yearshaveresultedinhotterfiresthataremoreunpredictable.Today’sbuildingsusemanymoresyntheticmaterialsthanthosebuilt30yearsagodid.Asaresult,whentheycatchfire,theyburnatamuchhighertemperatureandgiveoffmuchmoreenergythantheiroldercounterpartsdo.Furthermore,mostmodernbuildingsareextremelywellinsulated(绝缘的).Thatmeansthatwhentheycatchfire,theyholdmostofthefire’sheat.Hotterfiresresultinespeciallydangeroussituationsforfirefighters.Thefiresthemselvesaredangerous,ofcourse,butevenmoreproblematicarethesuper-hotgasescreatedbythefires.Thesecause“extremefirebehaviors,”atermfirefightersusetodescribequick-moving,life-threateningeventsatthesceneofafire.Theyincludeflashovers(跳火).Temperatureincreasessogreatlythatsomematerialsinanareaburnupatonce.Theyalsoincludebackdrafts(反风流),duringwhichoxygenrushesintoanarea,causingafireball.Themostdangerouseffectofabackdraftisthatitcanactuallytakeinalltheoxygenoutofaroomwherefirefightersareworking.Finally,therearegasexplosions(爆炸).Theyhappenwhenextremeheatcausesgasestospreadquickly.Americanfirefightershaveworkedhardtofightagainstthedangersofmodernfirefighting.Unfortunately,deathrateshaveremainednearlyunchangedduringthelast30years.That’sapoorshowingcomparedtoSwedenandGreatBritain.Bothofthosecountrieshavecutdeathratesamongfirefightersinhalfoverthesameperiod.WhyaretheBritishandtheSwedesmoresuccessfulatprotectingtheirfirefighters?Somewithinthefirefightingcommunitybelieveit’sbecausebothcountriesuseaprocedurecalled“3-Dfirefighting.”Fornow,mostAmericanfirecompanieswillstickwithtraditionalfirefightingstrategiesandbelievethat3-Dtechnique(技术)cannotbeeffective.Supportersofthetechniqueclaimthatitgreatlyreducesthelikelihoodofanextremefirebehavior.In2002,thefiredepartmentofGresham,OregonbecamethefirstintheUnitedStatestoaccept3-Dfirefightingtechniques.Thecompany’sbattalionchief,EdHartin,hasbecomeasupporterfortheprocedure,conductstrainings,andhaswrittenabookonthesubject.Maybetheuseof3-DfirefightingisheldbackbyitscostintheUnitedStates.56.Whatdoestheunderlinedword“counterparts”refertointhepassage?A.changesB.buildingsC.jobsD.fires57.Whatcanwelearnfromthepassageaboutbackdrafts?A.Backdraftsmakeallthematerialsburnupatonce.B.Backdraftscanbestoppedbygivingoffmoreoxygen.C.Backdraftscanmakethefirefightersdieofoxygenshortage.D.Backdraftsarefollowedbygasexplosionsandflashovers.58.WhydoestheauthorsaythattheUSmakesa“poorshowing”?A.B