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单选题Darwin'sVoyageontheHMSBeagleCharlesDarwinisfamedforthetheoryofevolution,whichwaspublishedintheworkOntheOriginofSpeciesin1859.AlargeportionofthetheorydevelopedduringanexploratoryoceanvoyageDarwinmadeaboardtheBritishRoyalNavyvesselHMSBeaglefrom1831to1836.Duringthatlongtrip,Darwinhadtheopportunitytoobserveplantandanimallifeinawidevarietyofecosystems,andthatledhimtoconcludethatmanyspeciesslowlyevolvedintotheirpresentformsduetothenecessityofsurvivingintheirenvironments.Afterreturninghome,Darwinspentthenextcoupleofdecadesanalyzingandrefininghisideasbeforemakingthempublicin1859.TheBeaglewasaten-gunnavalsloop—asmallshipbythestandardsoftheday—andwasequippedforlongexploratoryexpeditionswithitsgoalbeingtosurveythecoastalwatersofforeignlands.Theshipmadeitsfirstsuchvoyagefrom1826to1830,whereitmostlyconductedahydrographicsurveyofthecoastalwatersofSouthAmerica.Foritssecondvoyage,theBeaglewastocontinueitssurveywork.However,CaptainRobertFitzroywantedageologistonboardtoexaminethelandsincenonehadbeenpresentonthefirstvoyage,soDarwinwaseventuallycontactedtocarryoutthoseduties.SettingsailfromEnglandinDecember1831,theBeagle'sextensivevoyagetookittotheAtlanticandPacificcoastsofCentralAmerica,SouthAmerica,theGalapagosIslands,Tahiti,Australia,NewZealand,andMauritiusbeforetheshipreturnedtoEnglandinOctober1836.Duringthetrip,Darwinfrequentlywentashoretoexaminethelocalgeology,flora,andfauna,andhecollectednumeroussamplesandmadeextensivenotesabouteverythinghediscovered.Gradually,asthevoyagecontinued,hisobservationsledhimtohispioneeringnotionabouthowplantsandanimalsarrivedattheirpresentstates.Afterreturninghome,Darwinpublishedhisdiaryoftheexpeditionin1839.KnowntodayasTheVoyageoftheBeagle,thebookwaswellreceivedinitstimeandwentthroughseveralprintings.LargeportionsofthediaryservedasthebasisforDarwin'slaterwritings,includinghisworkonevolution.IncludedinthediaryweremanyofDarwin'sobservationsthatcontributedtoscientificstudies.Forexample,Darwinnotedthatinmanyplaces,bedsoffossilizedseashellshadbeenfoundathighelevations,whichindicatedthatthelandhadundergoneatremendoustransformationatsometimeinthepast.Darwinalsoobservedthatcoralatollsformedwhenvolcanicislandssank,leavingbehindcoralreefs.Buthisgreatestfindwasthediscrepancyinplantandanimallifeinplacesthatwereshortdistancesapartfromoneanother.Forinstance,thefloraandfaunaoftheAtlanticandPacificcoastsofPanamadifferedalargeamountdespitebeingrelativelyclosetoeachother.HefurtherrecordedthefactthatthevariousislandsoftheGalapagoshadsimilarplantsandanimalsbutthattheyhadevolvedwithslightdifferencesthathelpedthemsurviveontheparticularislandonwhichtheydwelled.ThemostfamousexampleofthisobservationisthefinchesDarwinnoticedashavingdifferent-shapedbeaks,eachofwhichwassuitedforthemainfoodsourceonitsparticularisland.IntheyearsfollowingthevoyageoftheBeagle,Darwincontemplatedhisfindingsandgraduallyarticulatedhisfamoustheory.Nevertheless,hefeltunreadytopublishhisworkbecausehewantedtoworkonotherprojectstogathermoreevidence.Then,inthe1850s,helearnedthathisideasweresimilartothoseofanothernaturalist,AlfredWallace,whohadbeenworkinginSoutheastAsiaforyearsandhadcometonearlyidenticalconclusionswithDarwin.Oncetheymadecontact,in1858,thetwomencollaboratedonapaperdiscussingevolution,makingitthefirstpublishedmentioningofthetheory.Then,fearfulthatWallacewouldpublishabookonthesubjectfirst,Darwin'sfriendsurgedhimtoputhisworkintoprint.TheresultwasOntheOriginofSpeciesin1859.Tohiscredit,WallaceneverfeltslightedandpubliclysupportedDarwinandhisworkwhenbothcameunderattack.AsfortheBeagle,itmadeathirdtripsimilartothefirsttwoandthenspenttimeservingasaguardshipinEngland'scoastalwaters.*Glossarysloop:asailingshipthathasasinglemasthydrographic:relatingtothescienceofmeasuringandmappingthesurfaceoftheEarth'swaters,mostlyforthepurposeofnavigationatoll:acoralreefintheshapeofaringthathasanenclosedornearlyenclosedlagoon
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单选题NeutronStarsWhilethelargeststarknowntomanisroughly2,000timesthediameteroftheEarth'ssun,therearealsostarssotinythattheyarenolargerthanasmallmetropolitanarea.Theseareneutronstars.Aneutronstarisextremelydenseandisessentiallythecorpseofagiantstarwhichcollapsedaftergoingsupernova.Despiteitssmallsize,aneutronstarhasamassgreaterthanoneandahalftimesthatofthesun,isamongthehotteststarsinthegalaxy,andhasoneofthestrongestmagneticfieldsofanyobjectinexistence.Wheneveraneutronstarforms,itbeginsspinningrapidly,whichcausestheelectromagneticenergyitemitstoappeartoblink,orpulse,toobserversontheEarth.Astronomerscallthesespinning,blinkingneutronstarspulsars.Astarmustreachacertainsize—roughlyfourtoeighttimesthesizeofthesun—tobeabletoformaneutronstar.Starssmallerthanthattypicallybecomewhitedwarfswhentheycollapsewhilethoselargerthanthatnormallytransformintoblackholesuponcollapsing.Theformationofaneutronstaroccurswhenasupernovadestroysastar'souterlayeryetleavesthedensecoreintact.Thecenterofthestarisusuallycomprisedofiron,butotherelementsmaybepresentinsmalleramounts.Withthestar'souterlayersgone,nuclearfusionisnolongerpossible,whichresultsingravityhavingnocounterbalancingoutwardforce.Therefore,gravityactsstronglyonthecoreandmakesitextremelydense.Asthisdensitygrowsinstrength,theelectronsandprotonsinthecore'satomsareforcedtogethertoformacoreofneutronsandneutrinos.Theneutronstarformsastructurewithdifferentlayers,muchlikeotherbodiesintheuniverse.Iftheneutronstarisrelativelyyoung,itisstillveryhot,soitssurfacemaybemoreliquidthansolidwhileitsinnercoreismuchdenserandmoresolidified.Aneutronstar'stemperatureisatitsheightsoonafteritsbirth,butthestargraduallybeginscoolingoffasitbecomesolderonaccountofthelossofneutrinos,whichstartflyingoffthestarassoonasitiscreated.Overtime,theseneutrinoscarryawayagreatamountofthestar'senergy,soitstemperaturefallstoalevelapproximatelyhalfofwhatitwasatitsgenesis.Nevertheless,evenafterthislossoftemperature,aneutronstarranksasoneofthehotteststarsintheuniverse.Inaddition,whenitforms,aneutronstarspinsatanextremelyhighrate—somewherebetweensixtyand600timespersecond.Thishighrotationisexplainedbythelawofconservationofangularmomentum,whichpointsoutthatanobjectrotatesatafasterratethemoreitisdrawninonitself.Thisissimilartothewaythatafigureskaterbeginsspinningfasterthemomentthatshepullsherarmstowardherbody.Theextremedensityofaneutronstarcreatesaverystrongelectromagneticfield,whichismostoftenobservedintheX-rayband.Thismagneticfieldisalignedalongadifferentaxisthanthespinningmotionofthestar,soitislikealighthousebeamrotatinginspace.IfthestarisalignedintherightwaywiththeEarth,astronomersusingradiotelescopearrayscanobservethisspinningmagneticfield.AstronomerJocelynBellfirstobservedthisphenomenonin1967,andsuchstarsweresooncalledpulsars.MostpulsarsemitelectromagneticenergyintheX-rayband,butsomeemititinthevisiblelightbandaswellasthegammarayband.Theseobservationsledtothediscoveryofmoreneutronstars—almostallofthempulsars—inthefollowingdecades.Somearecalledmillisecondpulsarsbecauseofthefactthattheyrotateasmanyas700timespersecond.Atpresent,astronomershavediscoverednearly2,000neutronstars;however,itisbelievedthatthenumberofneutronstarsisfargreatersinceallofthemcannotbeobservedfromtheEarthbecausetheirrotatingmagneticfieldsaremisalignedwiththeplanet.Inaddition,asneutronstarsage,thespeedoftheirrotationdecelerates,preventingthemfrombeingdiscoveredaseasilyasmoreswiftlyrotatingneutronstars.*Glossarynuclearfusion:areactioninwhichthenucleioflightatomsunitetoformthenucleiofheavieratomsneutrino:amasslessornearlymasslesslepton,anelementarytypeofparticlemillisecond:onethousandthofasecond
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单选题BritishTaxationandtheAmericanColoniesWhentheFrenchandIndianWarconcludedin1763,theresultwasanoverwhelmingBritishvictoryovertheFrenchthatresultedinthelosersbeingdrivenfrommostoftheirNorthAmericancolonies.TheBritishgovernment,foritspart,wasleftdeeplyindebt.Afterthehostilitiesended,theBritishParliamentenactedseveralnewtaxlawsintendedtoraiserevenuefromBritain'sAmericancoloniestopayforthewar.TheAmericancolonistshadnovoiceinParliamenttospeakfororagainsttheselaws,sotheendresultwasthattheydevelopedstrong,negativereactionstowhattheytermed"taxationwithoutrepresentation."Thecolonistsaccordinglyopposedthetaxes,andtheirprotestsescalatedtoviolenceandwereultimatelyaleadingcauseoftheAmericanRevolution.Fourmaintaxescreatedtensioninthecolonies:theSugarActof1764,theStampActof1765,theTownsendActsof1767,andtheTeaActof1773.Thefirst,theSugarAct,wasenactedtopreventthesmugglingofmolasses.UndertheMolassesActof1733,colonistshadtopayadutyofsixpencepergallonofmolasses.Yetcustomsofficialsroutinelyacceptedbribesofaroundoneandahalfpencepergallonandpermittedthemolassestobeshippeduntaxed.TheSugarActactuallyreducedthedutytothreepence,butthecolonistsstillrefusedtopayit.Onlywhenitwasloweredtoonepencein1766diditbecomecheapertopaythedutythanthebribes.TheBritishgovernmentsubsequentlyreceivedaround30,000poundsofrevenueperyear—arelativelysmallamountofmoney—fromthemolassestrade.ThemaineffectoftheSugarActwastomakethecolonistswonderiftheBritishhadtherighttointerfereintheiraffairs,particularlyinmattersoftrade.Nevertheless,theSugarActwasnotwidelyprotestedbecauseitprimarilyaffectedthoseinvolvedintradeandshipping.ThesamecannotbesaidoftheStampAct,whichhadawide-rangingeffectoneverycolony.Itmandatedthatmanydocumentsthecolonistsused,especiallythoserelatedtolegalaffairsandpublishing,couldonlybewrittenonpaperwithacrownrevenuestamponit.Essentially,thecolonistshadtobuyspecialpaperfromtheBritishgovernmentatahigherpricethannormalpaper.Regardingthisasadirectformoftaxation,thecolonistsprotestedtheactsovigorouslythatitwasrepealedin1766.Despitethissetback,theBritishgovernmentwasdeterminedtoextractrevenuefromthecolonies.TheTownsendActsweredesignedtotaxawidevarietyofimporteditemstoraisemoneytopaythesalariesofgovernmentofficialsinthecolonies.Onceagain,however,thecolonistsobjectedastheybelievedthatBritishcontrolofAmericancolonialgovernmentofficials'salarieswouldresultinmorewidespreadBritishinfluenceinthecolonies.AfterextensiveAmericanboycottsofBritishgoods,theactswererepealedin1770exceptforataxontea.This,inturn,ledtotheTeaAct,whichwasanattemptbytheBritishgovernmenttobestowamonopolyonthesaleofteainthecoloniestotheEastIndiaCompany.AmongthemostfamousreactionstothislawhappenedonthenightofDecember16,1773.AmericancolonistsdressedasIndiansstormedonboardBritishshipsinBostonHarborandcasttheircargoesofteaintothewaterinwhatcametobeknownastheBostonTeaParty.TheoppositeperceptionseachsidehadoftheroleofthecolonistsintheBritishEmpireweretherootcauseofthedifficultiesbetweentheopposingsides.TotheBritish,itappearedreasonabletotaxthecoloniststopayforthewarthatdrovetheencroachingFrenchoutofNorthAmerica.ThecolonistswerealsopartoftheglobalBritishEmpireandhadalwaysbeenregardedasasupportsystemforthemotherland.Butbythe1760s,theAmericancolonieshadexistedfornearly150yearsandhadattainedahighlevelofautonomy.ThoughthecoloniesstillbelongedtotheBritishEmpire,manycolonistsconsideredthemselvesAmericansratherthanBritish.ThiswasarecipefortroublewhentheBritishbeganmakingdemandsthecoloniststhoughtunreasonable,sothiseventuallyledtotheAmericanRevolutionandthefoundingofanewnation.*Glossarymolasses:athicksyrupmadebyrefiningsugarbribe:moneypaidtoapersonsuchasapublicofficialforthepurposeofevadingthelawcrown:referringtothesovereignpowerofamonarchy
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问答题 When companies have goods and services to sell
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问答题ThelionfishisatropicalspeciesnativetotheIndianandPacificoceans.Notedforitsvibrantcolors,thelionfishwasonceaprizedaquariumfish,especiallyinNorthAmerica.However,itsvoraciousappetiteledtoitattackingotherfishkeptinthesameaquariumsandresultedinmanyownersdisposingoftheirlionfishinnearbywaterways.Whilemanylionfishdiedinthewild,theyhavefoundhomesintheCaribbeanSeaandWesternAtlanticOcean,wheretheirnumbersareexploding.Theyareconsuminglargenumbersoffishincoralreefsandbeinggeneralnuisances,sopeoplearedevisingwaystogetridofthem.Fewfishactivelyhuntthelionfish,butthegrouperisone.Yetthegrouperisapopularfoodfisharoundtheworld,sofishermencommonlycatchit.Somepeoplehaveproposedenactingquotasonthenumberofgrouperscaughtinareaswithnumerouslionfish.Bydoingso,thegrouperpopulationcanincrease,andthentherewillbemoregrouperstohuntlionfish.Fishermenarenowbeingencouragednottoreleaseanylionfishtheycatchbuttokillthemeveniftheyhavenoplanstoeatthem.Diverswithspeargunsaresimilarlybeingaskedtoshootanylionfishtheyfind,especiallythoselivingincoralreefs.Whilethefishermenanddiversmaynotkilllargenumbersoflionfish,theycanactivelyreducetheirnumbers.Peoplelivingintropicalareasarepromotingtheconsumptionoflionfish.Thefish,whichtastedelicious,areconsideredadelicacyinChina.ByeducatingpeopleintheUnitedStatesandothercountriesabouthowgoodlionfishtastes,demandforthefishshouldincrease,somorefishermenwillstartcatchingthem.Thisshouldresultintherebeingfewerlionfishinsomeregions.DirectionsYouhave20minutestoplanandwriteyourresponse.Yourresponsewillbejudgedonthebasisofthequalityofyourwritingandonhowwellyourresponsepresentsthepointsinthelectureandtheirrelationshiptothepassage.Typically,aneffectiveresponsewillbe150-225words.QuestionSummarizethepointsmadeinthelecture,beingsuretoexplainhowtheycastdoubtonspecificpointsmadeinthereadingpassage.
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问答题 In recent years
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问答题
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问答题 Texas wild rice
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问答题 In the middle of the fourteenth century
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问答题AncientGreekhistorianHerodotuswroteaboutthePhoeniciansinhisworkTheHistories.Heclaimedthataround600B.C.,theycircumnavigatedAfricabysailingsouthfromtheRedSea,westaroundtheCapeofGoodHope,andthennorthalongsidethewesternpartofAfrica,whereupontheyenteredtheMediterraneanSeathroughtheStraitsofGibraltar.Thisjourneytookapproximatelythreeyearstoaccomplish.EversinceHerodotusmadehisclaim,othershavebeenskepticalaboutitforanumberofvalidreasons.Tobeginwith,whilethePhoeniciansconstructedgoodsailingships,theywerecoasthuggersnotintendedforrough,openseas.Theirsailsweresquareandthereforeunabletodomuchmorethancatchadirectbreeze,sotheshipshadlittleabilitytotackintocontrarywinds.ThiswouldhavebeentroublesomeonthenorthwardjourneybyAfrica'swestcoastbecausethewindmostlyblowsfromthenorth.ThePhoeniciansalsowouldhavebeenventuringintotheunknownsincetheywouldhavebeenunfamiliarwiththeAfricancoast,itscurrents,thelocationsofreefs,andtheprevailingwindsfornearlytheentirejourney.Thechancesarethattheirshipscouldnothavesurvivedthosedangersandeitherattemptedthejourneybutwereforcedtoturnbackorsanksomewherealongtheway.Finally,theweatheraroundtheCapeofGoodHopeissomeoftheworstintheworldduetothestrongwindsandhighwaves.Inotherareas,thewindscanbebecalmedforweeksatatime.ArecentattempttorecreatethevoyagewithareplicaPhoenicianshipprovedthedangeroftheweather.Thevoyageonlysucceededbecausetheshiphadsatellitenavigationaids,up-to-dateweatherreports,andanengineitusedwhenthewindwasnotblowing.DirectionsYouhave20minutestoplanandwriteyourresponse.Yourresponsewillbejudgedonthebasisofthequalityofyourwritingandonhowwellyourresponsepresentsthepointsinthelectureandtheirrelationshiptothepassage.Typically,aneffectiveresponsewillbe150-225words.QuestionSummarizethepointsmadeinthelecture,beingsuretospecificallyexplainhowtheyanswertheproblemsraisedinthereadingpassage.
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问答题 Around the world
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问答题CompletingtheEssayCompletethefollowingsampleessay.Usethephrasestohelpyouwriteyouressay.AgreeIagreewiththisstatement.Inmyopinion,___________________________________________________________________________________________________________Thefirstreasonisverysimple.___________________________________________________________________________________________________________Asecondreasonteachersareimportantisthat___________________________________________________________________________________________________________Athirdreasonisthat___________________________________________________________________________________________________________Teachersareclearlyofgreatimportancetothesuccessofaschool.___________________________________________________________________________________________________________DisagreeIbelieveteachersareimportanttoschools,butIdonotagreewiththestatement.___________________________________________________________________________________________________________Firstofall,___________________________________________________________________________________________________________Anotherreasonisthat___________________________________________________________________________________________________________Finally,___________________________________________________________________________________________________________Idisagreewiththestatementbecause___________________________________________________________________________________________________________
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问答题 Located in Giza, Egypt
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问答题CompletingtheEssayCompletethefollowingsampleessay.Usethephrasestohelpyouwriteyouressay.AgreeIbelievethat___________________________________________________________________________________________________________Thefirstreasonisthat___________________________________________________________________________________________________________Furthermore,Ibelieve___________________________________________________________________________________________________________Thefinalissueisthat___________________________________________________________________________________________________________Itiscleartomethat___________________________________________________________________________________________________________DisagreeWhileIunderstandwhypeoplemightsupporthavingthegovernmentpayforaccesstotheInternet,___________________________________________________________________________________________________________Ifeelthiswayforafewreasons.Oneisthat___________________________________________________________________________________________________________Asecondreasonisthat___________________________________________________________________________________________________________Lastly,___________________________________________________________________________________________________________ThegovernmentshouldnotpayforpeopletoaccesstheInternetsince___________________________________________________________________________________________________________
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问答题 Directions Read the question below
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问答题CompletingtheEssayCompletethefollowingsampleessay.Usethephrasestohelpyouwriteyouressay.SportsItisunfortunatethattheuniversityissufferingfromalackoffundsandcanonlysupportoneactivitysinceeachofthemisworthy.Butbecauseachoicemustbemade,___________________________________________________________________________________________________________Thefirstreasonisthat___________________________________________________________________________________________________________Universitiesarenotonlyplaceswherestudentsgotoimprovetheirminds,buttheyarealsoplaceswheretheycanimprovetheirbodies.___________________________________________________________________________________________________________Iwishtheschoolcouldprovidefundingforallthreeactivities,butsinceitcannot,thechoiceisclear:___________________________________________________________________________________________________________ArtTheuniversityhasatoughchoicetomake.Itmustchoosebetweensupportingsports,art,andvolunteering.Ilikeallthreeoptions,butIbelieve___________________________________________________________________________________________________________Onereasonisthat___________________________________________________________________________________________________________Anotherfactortoconsideristhat___________________________________________________________________________________________________________Inmyopinion,___________________________________________________________________________________________________________
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问答题
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问答题 Directions Read the question below
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