北京师范大学考博英语真题.docx

北京师范大学考博英语真题.docx

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北京师范大学考博英语真题

2015年北京师范大学考博英语真题

（总分68,做题时间90分钟）

1.ReadingComprehension

Thehumanearcontainstheorganforhearingandtheorganforbalance.Bothorgansinvolvefluid-filledchannelscontaininghaircellsthatproduceelectrochemicalimpulseswhenthehairsarestimulatedbymovingfluid.Theearcanbedividedintothreeregions:

outer,middle,andinner.Theouterearcollectssoundwavesanddirectsthemtotheeardrumseparatingtheouterearfromthemiddleear.Themiddleearconductssoundvibrationsthroughthreesmallbonestotheinnerear.Theinnerearisanetworkofchannelscontainingfluidthatmovesinresponsetosoundormovement.Toperformthefunctionofhearing,theearconvertstheenergyofpressurewavesmovingthroughtheairintonerveimpulsesthatmebrainperceivesassound.Vibratingobjects,suchasthevocalcordsofaspeakingperson,createwavesinmesurroundingair.Thesewavescausetheeardrumtovibratewiththesamefrequency.Thethreebonesofthemiddleearamplifyandtransmitthevibrationstotheovalwindow,amembraneonthesurfaceofthecochlea,theorganofhearing.Vibrationsofmeovalwindowproducepressurewavesinthefluidinsidemecochlea.Haircellsinthecochleaconverttheenergyofthevibratingfluidintoimpulsesthattravelalongtheauditorynervetothebrain.Theorganforbalanceisalsolocatedintheinnerear.Sensationsrelatedtobodypositionaregeneratedmuchlikesensationsofsound.Haircellsintheinnerearrespondtochangesinheadpositionwithrespecttogravityandmovement.Gravityisalwayspullingdownonthehairs,sendingaconstantseriesofimpulsestothebrain.Whenthepositionoftheheadchanges—aswhentheheadbendsforward—theforceonthehaircellschangesitsoutputofnerveimpulses.Thebraintheninterpretsthesechangestodeterminethehead'snewposition.

1.

Whatcanbeinferredabouttheorgansforhearingandbalance?

ABothorgansevolvedinhumansatthesametime.

BBothorganssendnerveimpulsestothebrain.

CBothorganscontainthesameamountoffluid.

DBothorgansarelocatedinmeear'smiddleregion.

2.

HearinginvolvesallofthefollowingEXCEPT______.

Amotionofthevocalcordssothattheyvibrate

Bstimulationofhaircellsinfluid-filledchannels

Camplificationofsoundvibrations

Dconversionofwaveenergyintonerveimpulses

3.

ItcanbeinferredfromParagraphs2and3thatthecochleaisapartof______.

Atheouterear

Bmeeardrum

Cthemiddleear

Dtheinnerear

4.

WhatcanbeinferredfromParagraph4aboutgravity?

AGravityhasanessentialroleinthesenseofbalance.

BTheearconvertsgravityintosoundwavesintheair.

CGravityisaforcethatoriginatesinthehumanear.

DTheorganforhearingisnotsubjecttogravity.

5.

Inthispassage,theauthormainlyexplains______.

Atheorgansofthehumanear

Bthefunctionofthehearing

Cthethreeregionsoftheear

Dhowtheearorganperformsthehearingandbalance

ThegeologyoftheEarth'ssurfaceisdominatedbytheparticularpropertiesofwater.PresentonEarthinsolid,liquid,andgaseousstates,waterisexceptionallyreactive.Itdissolves,transports,andprecipitatesmanychemicalcompoundsandisconstantlymodifyingthefaceoftheEarth.Evaporatedfromtheoceans,watervaporformsclouds,someofwhicharetransportedbywindoverthecontinents.Condensationfromthecloudsprovidestheessentialagentofcontinentalerosion:

rain.Precipitatedontotheground,thewatertricklesdowntoformbrooks,streams,andrivers,constitutingwhatiscalledthehydrographicnetwork.Thisimmensepolarizednetworkchannelsthewatertowardasinglereceptacle:

anocean.Gravitydominatesthisentirestepinthecyclebecausewatertendstominimizeitspotentialenergybyrunningfromhighaltitudestowardthereferencepointthatissealevel.Therateatwhichamoleculeofwaterpassesthroughthecycleisnotrandombutisameasureoftherelativesizeofthevariousreservoirs.Ifwedefineresidencetimeastheaveragetimeforawatermoleculetopassthroughoneofthethreereservoirs—atmosphere,continent,andocean—weseethatthetimesareverydifferent.Awatermoleculestays,onanaverage,elevendaysintheatmosphere,onehundredyearsonacontinentandfortythousandyearsintheocean.Thislastfigureshowstheimportanceoftheoceanastheprincipalreservoirofthehydrospherebutalsotherapidityofwatertransportonthecontinents.Avastchemicalseparationprocesstakesplacesduringtheflowofwateroverthecontinents.Solubleionssuchascalcium,sodium,potassium,andsomemagnesiumaredissolvedandtransported.Insolubleionssuchasaluminum,iron,andsiliconstaywheretheyareandformthethin,fertileskinofsoilonwhichvegetationcangrow.Sometimessoilsaredestroyedandtransportedmechanicallyduringflooding.Theerosionofthecontinentsthusresultsfromtwocloselylinkedandinterdependentprocesses,chemicalerosionandmechanicalerosion.Theirrespectiveinteractionsandefficiencydependondifferentfactors.

6.

Accordingtothepassage,cloudsareprimarilyformedbywater______.

Aprecipitatingontotheground

Bchangingfromasolidtoaliquidstate

Cevaporatingfromtheoceans

Dbeingcarriedbywind

7.

Thepassagesuggeststhatthepurposeofthe"hydrographicnetwork"isto______.

Adeterminethesizeofmoleculesofwater

Bpreventsoilerosioncausedbyflooding

CmovewaterfromtheEarth'ssurfacetotheoceans

Dregulatetherateofwaterflowfromstreamsandrivers

8.

Whatdeterminestherateatwhichamoleculeofwatermovesthroughthecycle,asdiscussedinthethirdparagraph?

AThepotentialenergycontainedinwater.

BTheeffectsofatmosphericpressureonchemicalcompounds.

CTheamountsofrainfallthatfallonthecontinents.

DTherelativesizeofthewaterstorageareas.

9.

AllofthefollowingareexamplesofsolubleionsEXCEPT______.

Amagnesium

Biron

Cpotassium

Dcalcium

10.

Theword"efficiency"inline21isclosestinmeaningto______.

Arelationship

Bgrowth

Cinfluence

Deffectiveness

Scientistshavelongunderstoodthatsupermassiveblackholesweighingmillionsorbillionsofsunscantearapartstarsthatcometooclose.Theblackhotelsgravitypullsharderonthenearestpartofthestar,animbalancethatpullsthestarapartoveraperiodofminutesorhours,onceitgetscloseenough.Scientistssaythisunevenpullingisnottheonlyhazardfacingthestar.Thestrainoftheseunbalancedforcescanalsotriggeranuclearexplosionpowerfulenoughtodestroythestarfromwithin.MatthieuBrassartandJean-PierreLuminetoftheObservatoiredeParisinMeudon,France,carriedoutcomputersimulationsofthefinalmomentsofsuchanunfortunatestar'slife,asitveeredtowardsasupermassiveblackhole.Whenthestargetscloseenough,theunevenforcesflattenitintoapancakeshape.Somepreviousstudieshadsuggestedthisflatteningwouldincreasethedensityandtemperatureinsidethestarenoughtotriggerintensenuclearreactionsthatwouldtearitapart.Butotherstudieshadsuggestedthatthepicturewouldbecomplicatedbyshockwavesgeneratedduringtheflatteningprocessandthatnonuclearexplosionshouldoccur.Thenewsimulationsinvestigatedtheeffectsofshockwavesindetail,andfoundthatevenwhentheireffectsareincluded,theconditionsfavoranuclearexplosion."Therewillbeanexplosionofthestar—itwillbecompletelydestroyed,"Brassartsays.Althoughtheexplosionobliteratesthestar,itsavessomeofthestar'smatterfrombeingdevouredbytheblackhole.Theexplosionispowerfulenoughtohurlmuchofthestar'smatteroutoftheblackhole'sreach,hesays.Thedevouringofstarsbyblackholesmayalreadyhavebeenobserved,althoughatamuchlaterstage.Itisthoughtmatseveralmonthsaftertheeventthatripsthestarapart,itsmatterstartsswirlingintotheholeitself.Itheatsupasitdoesso,releasingultravioletlightandX-rays.Ifstarsdisruptednearblackholesreallydoexplode,thentheycouldinprincipleallowtheseeventstobedetectedatamuchearlierstage,saysJulesHatpernofColumbiaUniversityinNewYork,US2."Itmaymakeitpossibletoseethedisruptionofthatstarimmediatelyifitgetshotenough,"hesays.Brassartagrees."PerhapsitcanbeobservedintheX-raysandgammarays,butit'ssomethingthatneedstobemorestudied,"hesays.SupernovaresearcherChrisFryeroftheLosAlamosNationalLaboratoryinLosAlamos,NewMexico,US3,saysthedeathsofthesestarsaredifficulttosimulate,andheisnotsurewhethertheresearchershaveproventheircasethattheyexplodeintheprocess.

11.

Somethingdestructivecouldhappentoastarthatgetstooclosetoablackhole.WhichofthefollowingdestructivestatementsisNOTmentionedinthepassage?

ATheblackholecouldtearapartthestar.

BTheblackholecouldtriggeranuclearexplosioninthestar.

CTheblackholecoulddwindleitssizeconsiderably.

DTheblackholecoulddevourthestar.

12.

Accordingtothethirdparagraph,researchersdifferedfromeachotherintheproblemof______.

Awhethernuclearreactionwouldoccur

Bwhetherthestarswouldincreaseitsdensityandtemperature

Cwhethershockwaveswouldoccur

Dwhethertheunevenforceswouldflattenthestars

13.

Accordingtothefourthparagraph,whichofthefollowingisNOTtrue?

ANonuclearexplosionwouldbetriggeredinsidethestar.

BThestarwouldbedestroyedcompletely.

CMuchofthestar'smatterthrownbytheexplosionwouldbebeyondtheblackhole'sreach.

DTheblackholewouldcompletelydevourthestar.

14.

Whatwillhappenseveralmonthsafterthe