新概念英語第四冊+Lesson+7+Bats+講義

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生詞和短語batn.蝙蝠strictlyadv.明確地utilitarianadj.實用的appreciationn.理解elapsev.障礙物hulln.消逝intervaln.船體receiptn.間隔apparatusn.收到shoaln.儀器herringn.魚群codn.鱈魚squeak9n.尖叫聲參考譯文動物發(fā)出的聲音不都是用作語言交際。我們只要看一看蝙蝠回聲定位這一極不尋常的發(fā)現(xiàn)，就可以探究一下聲音在什么情況下有絕對的實用價值。要透徹理解這句話的意義，我們應先回顧一下人類最近的幾項發(fā)明。大家都知道，在墻壁或山腰附近發(fā)出的喊聲，就會聽到回聲。固體障礙物越遠?；芈暦祷厮脮r間就越長。敲打船體所發(fā)了的聲音會從海底傳回來，測出回聲間隔的時間，便可算出該處海洋的深度。這樣就產(chǎn)生了目前各種船舶上普遍應用的回聲探測儀。任何固體者反射聲音，反射的聲音因物體的大小和性質(zhì)的不同而不同。魚群也反射聲音。從測定海深到測定魚群，這一進展比較容易。根據(jù)經(jīng)驗和改進了的儀器，不僅能夠確定魚群的位置，而且可以根據(jù)魚群回聲的特點分辨出是鯡魚、鱈魚，這是人們所熟悉的其他魚。人們發(fā)現(xiàn)，某些蝙蝠能發(fā)出尖叫聲，并能通過回聲來確定并躲開障礙物，或找到它們賴以為生的昆蟲。蝙蝠這種回聲定位常?？膳c雷達相比較，其原理是相似的。

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1utilitarian

adj.實用的，功利的參考例句：OntheutilitariansideAmericaneducationhasoutstriddentherestoftheworld.在實用方面美國教育已超越世界各國。Agoodclothcoatismoreutilitarianthanafurone.一件優(yōu)質(zhì)的布外衣要比一件毛皮外衣更有用。2strictly

adv.嚴厲地，嚴格地；嚴密地參考例句：Hisdoctorisdietinghimstrictly.他的醫(yī)生嚴格規(guī)定他的飲食。Theguestswereseatedstrictlyinorderofprecedence.客人嚴格按照地位高低就座。3appreciation

n.評價；欣賞；感謝；領(lǐng)會，理解；價格上漲參考例句：Iwouldliketoexpressmyappreciationandthankstoyouall.我想對你們所有人表達我的感激和謝意。I'llbesendingthemadonationinappreciationoftheirhelp.我將送給他們一筆捐款以感謝他們的幫助。4obstruction

n.阻塞，堵塞；障礙物參考例句：Shewaschargedwithobstructionofapoliceofficerintheexecutionofhisduty.她被指控妨礙警察執(zhí)行任務。Theroadwasclearedfromobstruction.那條路已被清除了障礙。5hull

n.船身；(果、實等的)外殼；vt.去(谷物等)殼參考例句：Theoutersurfaceofship'shullisveryhard.船體的外表面非常堅硬。Theboat'shullhasbeenstavedinbythetremendousseas.小船殼讓巨浪打穿了。6interval

n.間隔，間距；幕間休息，中場休息參考例句：Theintervalbetweenthetwotreesmeasures40feet.這兩棵樹的間隔是40英尺。Therewasalongintervalbeforeheanwseredthetelephone.隔了好久他才回了電話。7apparatus

n.裝置，器械；器具，設(shè)備參考例句：Theschool'saudioapparatusincludesfilmsandrecords.學校的視聽設(shè)備包括放映機和錄音機。Theyhadaveryrefinedapparatus.他們有一套非常精良的設(shè)備。8cod

n.鱈魚；v.愚弄；哄騙參考例句：Theysaltdowncodforwinteruse.他們腌鱈魚留著冬天吃。CodarefoundintheNorthAtlanticandtheNorthSea.北大西洋和北海有鱈魚。9squeak

n.吱吱聲，逃脫；v.（發(fā)出）吱吱叫，僥幸通過；（俚）告密參考例句：Idon'twanttohearanothersqueakoutofyou!我不想再聽到你出聲！Wewonthegame,butitwasanarrowsqueak.我們打贏了這場球賽，不過是僥幸取勝。10squeaks

n.短促的尖叫聲，吱吱聲(squeak的名詞復數(shù))v.短促地尖叫(squeak的第三人稱單數(shù))；吱吱叫；告密；充當告密者參考例句：Theupper-middle-classescommunicatewitheachotherininaudiblesqueaks,likebats.那些上中層社會的人交談起來象是蚊子在哼哼，你根本聽不見。來自辭典例句Shealwayssqueaksoutherideaswhensheisexcited.她一激動總是尖聲說出自己的想法。來自互聯(lián)網(wǎng)11steer

vt.駕駛，為…操舵；引導；vi.駕駛參考例句：Ifyoupushthecar,I'llsteerit.如果你來推車，我就來駕車。It'snousetryingtosteert