新概念英语第四册+Lesson+7+Bats+讲义

Lesson7Bats蝙蝠Inwhatwaydoesecho-locationinbatsplayanutilitarian1role?Notallsoundsmadebyanimalsserveaslanguage,andwehaveonlytoturntothatextraordinarydiscoveryofecho-locationinbatstoseeacaseinwhichthevoiceplaysastrictly2utilitarianrole.Togetafullappreciation3ofwhatthismeanswemustturnfirsttosomerecenthumaninventions.Everyoneknowsthatifheshoutsinthevicinityofawalloramountainside,anechowillcomeback.Thefurtheroffthissolidobstruction4,thelongertimewillelapseforthereturnoftheecho.Asoundmadebytappingonthehull5ofashipwillbereflectedfromtheseabottom,andbymeasuringthetimeinterval6betweenthetapsandthereceiptoftheechoes,thedepthoftheseaatthatpointcanbecalculated.Sowasborntheecho-soundingapparatus7,nowingeneraluseinships.Everysolidobjectwillreflectasound,varyingaccordingtothesizeandnatureoftheobject.Ashoaloffishwilldothis.Soitisacomparativelysimplestepfromlocatingtheseabottomtolocatingashoaloffish.Withexperience,andwithimprovedapparatus,itisnowpossiblenotonlytolocateashoalbuttotellifitisherring,cod8,orotherwell-knownfish,bythepatternofitsecho.Ithasbeenfoundthatcertainbatsemitsqueaks10andbyreceivingtheechoes,theycanlocateandsteer11clearofobstacles--orlocateflyinginsectsonwhichtheyfeed.Thisecho-locationinbatsisoftencomparedwithradar12,theprincipleofwhichissimilar.MAURICEBURTONCuriositiesofanimallifeNewwordsandexpressions生词和短语batn.蝙蝠strictlyadv.明确地utilitarianadj.实用的appreciationn.理解elapsev.障碍物hulln.消逝intervaln.船体receiptn.间隔apparatusn.收到shoaln.仪器herringn.鱼群codn.鳕鱼squeak9n.尖叫声参考译文动物发出的声音不都是用作语言交际。我们只要看一看蝙蝠回声定位这一极不寻常的发现，就可以探究一下声音在什么情况下有绝对的实用价值。要透彻理解这句话的意义，我们应先回顾一下人类最近的几项发明。大家都知道，在墙壁或山腰附近发出的喊声，就会听到回声。固体障碍物越远。回声返回所用时间就越长。敲打船体所发了的声音会从海底传回来，测出回声间隔的时间，便可算出该处海洋的深度。这样就产生了目前各种船舶上普遍应用的回声探测仪。任何固体者反射声音，反射的声音因物体的大小和性质的不同而不同。鱼群也反射声音。从测定海深到测定鱼群，这一进展比较容易。根据经验和改进了的仪器，不仅能够确定鱼群的位置，而且可以根据鱼群回声的特点分辨出是鲱鱼、鳕鱼，这是人们所熟悉的其他鱼。人们发现，某些蝙蝠能发出尖叫声，并能通过回声来确定并躲开障碍物，或找到它们赖以为生的昆虫。蝙蝠这种回声定位常常可与雷达相比较，其原理是相似的。

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1utilitarian

adj.实用的，功利的参考例句：OntheutilitariansideAmericaneducationhasoutstriddentherestoftheworld.在实用方面美国教育已超越世界各国。Agoodclothcoatismoreutilitarianthanafurone.一件优质的布外衣要比一件毛皮外衣更有用。2strictly

adv.严厉地，严格地；严密地参考例句：Hisdoctorisdietinghimstrictly.他的医生严格规定他的饮食。Theguestswereseatedstrictlyinorderofprecedence.客人严格按照地位高低就座。3appreciation

n.评价；欣赏；感谢；领会，理解；价格上涨参考例句：Iwouldliketoexpressmyappreciationandthankstoyouall.我想对你们所有人表达我的感激和谢意。I'llbesendingthemadonationinappreciationoftheirhelp.我将送给他们一笔捐款以感谢他们的帮助。4obstruction

n.阻塞，堵塞；障碍物参考例句：Shewaschargedwithobstructionofapoliceofficerintheexecutionofhisduty.她被指控妨碍警察执行任务。Theroadwasclearedfromobstruction.那条路已被清除了障碍。5hull

n.船身；(果、实等的)外壳；vt.去(谷物等)壳参考例句：Theoutersurfaceofship'shullisveryhard.船体的外表面非常坚硬。Theboat'shullhasbeenstavedinbythetremendousseas.小船壳让巨浪打穿了。6interval

n.间隔，间距；幕间休息，中场休息参考例句：Theintervalbetweenthetwotreesmeasures40feet.这两棵树的间隔是40英尺。Therewasalongintervalbeforeheanwseredthetelephone.隔了好久他才回了电话。7apparatus

n.装置，器械；器具，设备参考例句：Theschool'saudioapparatusincludesfilmsandrecords.学校的视听设备包括放映机和录音机。Theyhadaveryrefinedapparatus.他们有一套非常精良的设备。8cod

n.鳕鱼；v.愚弄；哄骗参考例句：Theysaltdowncodforwinteruse.他们腌鳕鱼留着冬天吃。CodarefoundintheNorthAtlanticandtheNorthSea.北大西洋和北海有鳕鱼。9squeak

n.吱吱声，逃脱；v.（发出）吱吱叫，侥幸通过；（俚）告密参考例句：Idon'twanttohearanothersqueakoutofyou!我不想再听到你出声！Wewonthegame,butitwasanarrowsqueak.我们打赢了这场球赛，不过是侥幸取胜。10squeaks

n.短促的尖叫声，吱吱声(squeak的名词复数)v.短促地尖叫(squeak的第三人称单数)；吱吱叫；告密；充当告密者参考例句：Theupper-middle-classescommunicatewitheachotherininaudiblesqueaks,likebats.那些上中层社会的人交谈起来象是蚊子在哼哼，你根本听不见。来自辞典例句Shealwayssqueaksoutherideaswhensheisexcited.她一激动总是尖声说出自己的想法。来自互联网11steer

vt.驾驶，为…操舵；引导；vi.驾驶参考例句：Ifyoupushthecar,I'llsteerit.如果你来推车，我就来驾车。It'snousetryingtosteert