Californiaisalandofvarietyandcontrast.Almosteverytypeofphysicallandfeature，sortofarcticicefieldsandtropicaljunglescanbefoundwithinitsborders.Sharplycontrastingtypesoflandoftenlieveryclosetooneanother.PeoplelivinginBakersfield，forinstance，canvisitthePacificOceanandthecoastalplain，thefertileSanJoaquinValley，thearidMojaveDesert，andthehighSierraNevada，allwithinaradiusofabout100miles.Inotherareasitispossibletogosnowskiinginthemorningandsurfingintheeveningofthesameday，withouthavingtotravellongdistance.ContrastaboundsinCalifornia.ThehighestpointintheUnitedStates(outsideAlaska)isinCalifornia，andsoisthelowestpoint(includingAlaska)。MountWhitney，14，494feetabovesealevel，isseparatedfromDeathValley，282feetbelowsealevel，byadistanceofonly100miles.Thetwoareashaveadifferenceinaltitudeofalmostthreemiles.Californiahasdeep，clearmountainlakeslikeLakeTahoe，thedeepestinthecountry，butitalsohasshallow，saltydesertlakes.IthasLakeTulainyo，12，020feetabovesealevel，andthelowestlakeinthecountry，theSaltonSea，236feetbelowsealevel.Someofitslakes，likeOwensLakeinDeathValley，arenotlakesatall：theyaredrieduplakebeds.Inadditiontomountains，lakes，valleys，deserts，andplateaus，CaliforniahasitsPacificcoastline，stretchinglongerthanthecoastlinesofOregonandWashingtoncombined.

1.WhichofthefollowingisthelowestpointintheUnitedStates?

A.LakeTulainyoB.MojavedesertC.DeathValleyD.TheSaltonSea

2.WhereisthehighestpointintheUnitedStateslocated?

A.LakeTahoe.

B.SierraNevada.C.MountWhitney.

D.Alaska.

3.HowfarawayisDeathValleyfromMountWhitney?

A.About3miles.

D.14，494feet.

4.WhichofthefollowingisNOTmentionedinthepassageasbeingwithinaradiusofabout100milesofBakersfield?

A.ThePacificOcean.

B.SanJoaquinValley.

C.MojaveDesert.

D.OregonandWashington.

5.WhichstatementbestdemonstratesthatCaliforniaisalandofvarietyandcontrast?

A.ThehighestlakeinCaliforniaisLakeTulainyo.

B.ItispossibletogosurfingandsnowskiinginsomepartsofCaliforniawithouthavingtotravellongdistance.

C.SierraNevada，SanJoaquinValley，MojaveDesertandthePacificOceanallliewithinaradiusofabout100miles.

D.OwensLake，inDeathValley，isnotreallyalakeatall.

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.

汉译英：暮色中，河湾里落满云霞，与天际的颜色混合一起，分不清哪是流云哪是水湾。也就在这一幅绚烂的图画旁边，在河湾之畔，一群羊正在低头觅食。它们几乎没有一个顾得上抬起头来，看一眼这美丽的黄昏。也许它们要抓紧时间，在即将回家的最后一刻再次咀嚼。这是黄河滩上的一幕。牧羊人不见了，他不知在处歇息。只有这些美生灵自由自在地享受着这个黄昏。这儿水草肥美，让它们长得肥滚滚的，像些胖娃娃。如果走近了，会发现它们那可爱的神情，洁白的牙齿，那丰富而单纯的表情。如果稍稍长久一点端详这张张面庞，还会生出无限的怜悯。

EinsteinwontheNobelPrizein1921andenjoyedgreatfameinGermanyuntiltheriseofNazism____hewasexpelledfromGermanybecausehewasaJew.

AlthoughSPanish，heattendedthecourse.