It is hard to track the blue whale, the ocean’s largest creature, which has almost been killed off by commercial whaling and is now listed as an endangered species. Attaching rad
树图思维导图提供 2015年12月英语四级阅读真题练习及答案(1) 在线思维导图免费制作,点击“编辑”按钮,可对 2015年12月英语四级阅读真题练习及答案(1) 进行在线思维导图编辑,本思维导图属于思维导图模板主题,文件编号是:69030fe1070d8ca1a91e7cb385f0d24b
2015年12月英语四级阅读真题练习及答案(1)思维导图模板大纲
Itishardtotrackthebluewhale,theocean’slargestcreature,whichhasalmostbeenkilledoffbycommercialwhalingandisnowlistedasanendangeredspecies.Attachingradiodevicestoitisdifficult,andvisualsightingsaretoounreliabletogiverealinsightintoitsbehavior.
Sobiologistsweredelightedearlythisyearwhen,withthehelpoftheNavy,theywereabletotrackaparticularbluewhalefor43days,monitoringitssounds.ThiswaspossiblebecauseoftheNavy’sformerlytop-secretsystemofunderwaterlisteningdevicesspanningtheoceans.
TrackingwhalesisbutoneexampleofanexcitingnewworldjustopeningtocivilianscientistsafterthecoldwarastheNavystartstoshareandpartlyuncoveritsglobalnetworkofunderwaterlisteningsystembuiltoverthedecadestotracktheshipsofpotentialenemies.
Earthscientistsannouncedatanewsconferencerecentlythattheyhadusedthesystemforcloselymonitoringadeep-seavolcaniceruption(爆发)forthefirsttimeandthattheyplansimilarstudies.
Otherscientistshaveproposedtousethenetworkfortrackingoceancurrentsandmeasuringchangesinoceanandglobaltemperatures.
Thespeedofsoundinwaterisroughlyonemileasecond—slowerthanthroughlandbutfasterthanthroughair.Whatismostimportant,differentlayersofoceanwatercanactaschannelsforsounds,focusingtheminthesamewayastethoscope(听诊器)doeswhenitcarriesfaintnoisesfromapatient’schesttoadoctor’sear.Thisfocusingisthemainreasonthatevenrelativelyweaksoundsintheocean,especiallylow-frequencyones,canoftentravelthousandsofmiles.
A)anefforttoprotectanendangeredmarinespecies
B)thecivilianuseofamilitarydetectionsystem
C)theexposureofaU.S.Navytop-secretweapon
D)anewwaytolookintothebehaviorofbluewhales
A)totraceandlocateenemyvessels
B)tomonitordeep-seavolcaniceruptions
C)tostudythemovementofoceancurrents
D)toreplacetheglobalradiocommunicationsnetwork
A)thesophisticatedtechnologyoffocusingsoundsunderwater
B)thecapabilityofsoundtotravelathighspeed
C)theuniquepropertyoflayersofoceanwaterintransmittingsound
D)low-frequencysoundstravelingacrossdifferentlayersofwater
A)newradiodevicesshouldbedevelopedfortrackingtheendangeredbluewhales
B)bluewhalesarenolongerendangeredwiththeuseofthenewlisteningsystem
C)opinionsdifferastowhethercivilianscientistsshouldbeallowedtousemilitarytechnology
D)militarytechnologyhasgreatpotentialincivilianuse
A)Itisnowpartlyaccessibletocivilianscientists.
B)Ithasbeenreplacedbyamoreadvancedsystem.
C)Itbecameuselesstothemilitaryafterthecoldwar.
D)Itisindispensableinprotectingendangeredspecies
参考答案
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大学英语四六级考试CET46
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