安全发展的基本任务是()
更新时间:2024-11-16 04:26:01 A、保障人民群众的生命财产安全A
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Hewasluredintoacrimehewouldnot____________havecommitted.
Heresented_____towait.Heexpectedtheminister_____himatonce.
汉译英:手机改变了人与人之间的关系。通常有注意到会议室的门上的告示,写着―关闭手机。‖然而,会议室仍然充满着铃声。我们都是普通人,没有很多重要的事情。但是,我们也不愿轻易关闭手机。打开手机象征着我们与世界的联系。手机反映出我们的社交饥渴。我们经常看到,一个人走着走着,就突然停下来了,眼睛盯着他的手机,不管他在那里,无论是在道路中心或旁边有厕所。
_____atinthisway,thepresenteconomicsituationdoesn'tseemsogloomy.
AsGilbertWhite,Darwin,andothersobservedlongago,allspeciesappeartohavetheinnatecapacitytoincreasetheirnumbersfromgenerationtogeneration.Thetaskforecologistsistountangletheenvironmentaandbiologicalfactorsthatholdthisintrinsiccapacityforpopulationgrowthincheckoverthelongrun.Thegreatvarietyofdynamicbehaviorsexhibitedbydifferentpopulationmakesthistaskmoredifficult:sompopulationsremainroughlyconstantfromyeartoyear;othersexhibitregularcyclesofabundanceandscarcity;stillothersvarywildly,withoutbreaksandcrashesthatareinsomecasesplainlycorrelatedwiththeweather,andinothercasesnot.Toimposesomeorderonthiskaleidoscopeofpatterns,oneschoolofthoughtproposesdividingpopulationsintotwogroups.Theseecologistspositthattherelativelysteadypopulationshavedensity-dependentgrowthparameters;thatis,ratesofbirth,death,andmigrationwhichdependstronglyonpopulationdensity.Thehighlyvaryingpopulationshavedensity-independentgrowthparameters,withvitalratesbuffetedbyenvironmentalevents;theseratesfluctuateinawaythatiswhollyindependentofpopulationdensity.Thisdichotomyhasitsuses,butitcancauseproblemsiftakentooliterally.Foronething,nopopulationcanbedrivenentirelybydensity-independentfactorsallthetime.Nomatterhowseverelyorunpredictablybirth,death,andmigrationratesmaybefluctuatingaroundtheirlong-termaverages,iftherewerenodensity-dependenteffects,thepopulationwould,inthelongrun,eitherincreaseordecreasewithoutbound(barringamiraclebywhichgainsandlossescanceledexactly)。Putanotherway,itmaybethatonaverage99percentofalldeathsinapopulationarisefromdensity-independentcauses,andonlyonepercentfromfactorsvaryingwithdensity.Thefactorsmakinguptheonepercentmayseemunimportant,andtheircausemaybecorrespondinglyhardtodetermine.Yet,whetherrecognizedornot,theywillusuallydeterminethelong-termaveragepopulationdensity.Inordertounderstandthenatureoftheecologist’sinvestigation,wemaythinkofthedensity-dependenteffectsongrowthparametersasthesignalecologistsaretryingtoisolateandinterpret,onethattendstomakethepopulationincreasefromrelativelylowvaluesordecreasefromrelativelyhighones,whilethedensity-independenteffectsacttoproducenoiseinthepopulationdynamics.Forpopulationsthatremainrelativelyconstant,orthatoscillatearoundrepeatedcycles,thesignalcanbefairlyeasilycharacterizedanditseffectsdescribed,eventhoughthecausativebiologicalmechanismmayremainunknown.Forirregularlyfluctuatingpopulations,wearelikelytohavetoofewobservationstohaveanyhopeofextractingthesignalfromtheoverwhelmingnoise.Butitnowseemsclearthatallpopulationsareregulatedbyamixtureofdensity-dependentanddensity-independenteffectsinvaryingproportions.
1.Theauthorofthetextisprimarilyconcernedwith
[A]Discussingtwocategoriesoffactorsthatcontrolpopulationgrowthandassessingtheirrelativeimportance.
[B]Describinghowgrowthratesinnaturalpopulationsfluctuateovertimeandexplainingwhythesechangesoccur.
[C]Proposingahypothesisconcerningpopulationsizeandsuggestingwaystotestit.
[D]Posingafundamentalquestionaboutenvironmentalfactorsinpopulationgrowthandpresentingsomecurrentlyacceptedanswer.
2.Itcanbeinferredfromthetextthattheauthorconsidersthedichotomydiscussedtobe
[A]Applicableonlytoerraticallyfluctuatingpopulations.
[B]instrumental,butonlyifitslimitationsarerecognized.
[C]Dangerouslymisleadinginmostcircumstances.
[D]Acompleteandsufficientwaytoaccountforobservedphenomena.
3.tothetext,allofthefollowingbehaviorshavebeenexhibitedbydifferentpopulationsEXCEPT
[A]Roughlyconstantpopulationlevelsfromyeartoyear.
[B]Regularcyclesofincreasesanddecreasesinnumbers.
[C]Erraticincreasesinnumberscorrelatedwiththeweather.
[D]Uncheckedincreasesinnumbersovermanygenerations.
4.Thediscussionconcerningpopulationinthethirdparagraphservesprimarilyto
[A]Demonstratethedifficultiesecologistsfaceinstudyingdensity-dependentfactorslimitingpopulationgrowth.
[B]Advocatemorerigorousstudyofdensity-dependentfactorsinpopulationgrowth.
[C]Provethatthedeathratesofanypopulationareneverentirelydensity-independent.
[D]underlinetheimportanceofevensmalldensity-dependentfactorsinregulatinglong-termpopulationdensities.
5.Inthetext,theauthordoesallofthefollowingEXCEPT
[A]Citetheviewsofotherbiologists.
[B]Defineabasicproblemthatthetextaddresses.
[C]Presentconceptualcategoriesusedbyotherbiologists.
[D]Describetheresultsofaparticularstudy.