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某同学在进行组织培养过程中,发现只分裂而不分化出芽和根,可能原因是()

A、未见阳光
B、培养时间不到
C、培养基营养过多
D、细胞分裂素和生长素配比不对
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Modern____perhapscausesmoreproblemsthanitsolves.

Scatteredthroughtheseasoftheworldarebillionsoftonsofsmallplantsandanimalscalledplankton.Mostoftheseplantsandanimalsaretoosmallforthehumaneyetosee.Theydriftaboutlazilywiththecurrents,providingabasicfoodformanylargeranimals.Planktonhasbeendescribedastheequivalentofthegrassesthatgrowonthedrylandcontinents,andthecomparisonisanappropriateone.Inpotentialfoodvaluehowever,planktonfaroutweighsthatofthelandgrasses.Onescientisthasestimatedthatwhilegrassesoftheworldproduceabout49billiontonsofvaluablecarbohydrateseachyear.Thesea’splanktongeneratesmorethantwiceasmuch.

Despiteitsenormousfoodpotential,littleeffortwasmadeuntilrecentlytofarmplanktonaswefarmgrassesonland.Nowmarinescientistshaveatlastbeguntostudythispossibility,especiallyasthesea’sresourcesloomevenmoreimportantasameansoffeedinganexpandingworldpopulation.

Nooneyethasseriouslysuggestedthat“planktonburgers”maysoonbecomepopulararoundtheworld.Asapossiblefarmedsupplementaryfoodsource,however,planktonisgainingconsiderableinterestamongmarinescientists.

Onetypeofplanktonthatseemstohavegreatharvestpossibilitiesisatinyshrimplikecreaturecalledkrill.Growingtotwoorthreeincheslong,krillprovidethemajorfoodforthegiantbluewhale,thelargestanimalevertoinhabittheEarth.Realizingthatthiswhalemaygrow100feetandweigh150tonsatmaturity,itisnotsurprisingthateachonedevoursmorethanonetonofkrilldaily.

Krillswimaboutjustbelowthesurfaceinhugeschoolssometimesmileswide,mainlyinthecoldAntarctic.Becauseoftheirpinkcolor,theyoftenappearasasolidreddishmasswhenviewedfromashiporfromtheair.Krillareveryhighinfoodvalue.Apoundofthesecrustaceanscontainsabout460calories—aboutthesameasshrimporlobster,towhichtheyarerelated.

Ifthekrillcanfeedsuchhugecreaturesaswhales,manyscientistsreason,theymustcertainlybecontendersasnewfoodsourceforhumans.

1.Whichofthefollowingbestportraystheorganizationofthepassage?

A.Theauthorpresentstheadvantagesanddisadvantagesofplanktonasafoodsource.

B.Theauthorquotespublicopiniontosupporttheargumentforfarmingplankton.

C.Theauthorclassifiesthedifferentfoodsourcesaccordingtoamountofcarbohydrate.

D.Theauthormakesageneralstatementaboutplanktonasafoodsourceandthenmovestoaspecificexample.

2.Accordingtothepassage,whyisplanktonregardedtobemorevaluablethanlandgrasses?

A.Itiseasiertocultivate.

B.Itproducesmorecarbohydrates.

C.Itdoesnotrequiresoil.

D.Itismorepalatable.

3.Whydoestheauthormention“planktonburgers”?

A.Todescribetheappearanceofonetypeofplankton.

B.Toillustratehowmuchplanktonawhaleconsumes.

C.Tosuggestplanktonasapossiblefoodsources.

D.Tocomparethefoodvaluesofbeefandplankton.

4.Whatismentionedasoneconspicuousfeatureofkrill?

A.Theyarethesmallestmarineanimals.

B.Theyarepinkincolor.

C.Theyaresimilarinsizetolobsters.

D.Theyhavegrasslikebodies.

5.Theauthormentionsallofthefollowingasreasonswhyplanktoncouldbeconsideredahumanfoodsourceexceptthatitis___.

A.highinfoodvalue.

B.inabundantsupplyintheoceans.

C.anappropriatefoodforotheranimals.

D.freeofchemicalsandpollutants.

Marytiptoedoverandtooktheclockawaybecauseshehatedtohearit()whenshewastryingtogotosleep.

PartIIVocabularyandStructure

Directions:Inthisparttherearefortyincompletesentences.Eachsentenceisfollowedbyfourchoices.ChoosetheonethatbestcompletesthesentenceandthenmarkyouranswerontheAnswerSheet.

21.Theteacherthestudentsonatourthroughtheartmuseum.

A.madeB.indicatedC.forcedD.took

22.Tom’sparentsdiedwhenhewasachild,sohewasbyhisrelatives.

A.grownupB.broughtupC.raisedD.fedup

23.Hereismycard.Let’skeepin.

A.touchB.relationC.connectionD.friendship

24.Sofarthereisnoproofpeoplefromotherplanetsdoexist.

A.whichB.howC.whatD.that

25.Thenewspapersreportedyesterdayseveralontheboundariesofthesetwocountries.

A.incidentsB.happeningsC.eventsD.accidents

26.We’veworkedouttheplanandnowwemustputitinto.

A.factB.realityC.practiceD.deed

27.Hedidn’tandsohefailedtheexamination.

A.workenoughhardB.hardworkenoughC.hardenoughworkD.workhardenough

28.NotuntilMr.SmithcametoChinawhatkindofcountrysheis.

A.heknewB.hedidn’tknowC.didheknowD.hecouldn’tknow

29.Scientistssayitmaybetenyearsthismedicinewasputtouse.

A.sinceB.beforeC.afterD.when

30.Insomecountries,iscalled“equality”doesnotreallymeanequalrightsforallpeople.

A.thatB.whatC.whichD.how

31.Wedidn’tknowhistelephonenumber,otherwisewehim.

A.wouldtelephoneB.wouldhavetelephone

C.hadtelephonedD.musthavetelephoned

32.We’vemissedthelastbus,I’mafraidwehavenobuttotakeataxi.

A.wayB.possibilityC.choiceD.selection

33.Luckily,mostsheepthefloodlastmonth.

A.enduredB.survivedC.livedD.passed

34.Myparentsalwaysletmehavemyownofliving.

A.wayB.methodC.mannerD.fashion

35.Likeotherlanguageskills,readingrequirespractice.

A.themostofB.muchoftheC.mostoftheD.moreofthe

36.Itisonlythroughpracticeonewillbeabletoswimskillfully.

A.whatB.whoC.thatD.which

37.Thebrainiscapableofignoringpainmessageoftoconcentrateonotheractivities.

A.itallowedB.isitallowedC.allowedD.allowedit

38.Don’tworry,Ihavealreadythemthedecision.

A.informed;withB.informed;ofC.informed;forD.informed;that

39.Thechildwassorryhismotherwhenhearrivedatthestation.

A.tomissB.havingmissedC.missingD.tohavemissed

40.Iwonderwhyhetodiscusstheproblematthemeeting.

A.declinedB.rejectedC.refusedD.delayed

41.Youcanhangupwhatyoulikeonthesewalls.

A.bareB.emptyC.blankD.vacant

42.Accordingtoa,themajoritywouldratherhavenewspaperswithoutagovernmentthanagovernmentwithoutnewspapers.

A.electionB.campaignC.pollD.vote

43.Thepopulationofthevillagehasdecreased150to500.

A.inB.atC.byD.with

44.ItseemsthatthereisthatIcan’tdo.

A.nothingB.anythingC.everythingD.none

45.Theyareoftencaringmoreaboutanimalsthanhumanbeings.

A.accusedifB.accusedwithC.chargedofD.chargedfor

46.agoodbeginningismade,thewordishalfdone.

A.AssoonasB.WhileC.AsD.Once

47.Georgecouldnothisfoolishmistake.

A.accountinB.countonC.countforD.accountfor

48.Wecameintothisfieldlate,sowemustworkhardtothelosttime.

A.makeupforB.makeoutC.keepupwithD.putupwith

49.Thenewlawwillcameintoonthedayitispassed.

A.effectB.useC.serviceD.existence

50.Wecanseparatethemixtureintothepurechemicalcompoundsitiscomposed.

A.inwhichB.ofwhatC.ofwhichD.fromwhich

51.Mrs.Lincolnhasthatsheisunabletogetajob.

A.suchsmalleducationB.solittleeducation

C.asuchlittleeducationD.asosmalleducation

52.Shecan’tpreventherlittleboyshootingbirds.

A.from;toB.on;atC.with;upD.from;at

53.Manycountriesareincreasingtheiruseofnaturalgas,windandotherformsof.

A.energyB.sourceC.powerD.material

54.Adarkenedskyinthedaytimeisusuallyandindicationthatastormis.

A.possiblecomingB.abouttotakeplace

C.closebyD.expectedtobesevere

55.Weallknowthatspeaklouderthanwords.

A.movementsB.performanceC.operationsD.actions

56.,hecouldnotcoverthewholedistanceinfifteenminutes.

A.FastashecanB.Ashecanranfast

C.IfhecanranfastD.Sinceheranfast

57.Agriculturalproductioninthatcountryhasincreasedinrecentyears.

A.vastlyB.strikinglyC.considerablyD.extremely

58.Peterhasplannedtosomemoneyeverymonthsothathecanbuyausedcarnextyear.

A.setasideB.setupC.setinD.setalong

59.AlthoughIspoketohimmanytimes,henevertookanyofwhatIsaid.

A.attentionB.noticeC.warningD.observation

60.Theyovercameallthedifficultiesandfulfilledtheplanthreemonthsaheadoftime,issomethingwehadnotexpected.

A.thatB.whatC.itD.which

TEXTC

Therearetwofactorswhichdetermineanindividual'sintelligence.Thefirstisthesortofbrainheisbornwith.

Humanbrainsdifferconsiderably,somebeingmorecapablethanothers.Butnomatterhowgoodabrainhehas

tobeginwith,anindividualwillhavealoworderofintelligenceunlesshehasopportunitiestolearn.Sothe

secondfactoriswhathappenstotheindividual—thesortofenvironmentinwhichheisbroughtup.Ifan

individualishandicapped(不利)environmentally,itislikelythathisbrainwillfailtodevelopandhewillnever

attainthelevelofintelligenceofwhichheiscapable.Theimportanceofenvironmentindetermininganindividual'sintelligencecanbedemonstratedbythecasehistoryoftheidenticaltwins,PeterandMark.Beingidentical,thetwinshadidenticalbrainsatbirth,andtheirgrowthprocesseswerethesame.Whenthetwinswerethreemonthsold,theirparentsdied,andtheywere

placedinseparatefoster(抚养)homes.Peterwasraisedbyparentsoflowintelligenceinanisolatedcommunity

withpooreducationalopportunities.Markwasrearedinthehomeofwell-to-doparentswhohadbeentocollege.Hewasreadtoasachild,senttogoodschools,andgiveneveryopportunitytobestimulated

intellectually.Thisenvironmentaldifferencecontinueduntilthetwinswereintheirlateteens,whentheywere

giventeststomeasuretheirintelligence.Mark'sI.Q.was125,twenty-fivepointshigherthantheaverageand

fullyfortypointshigherthanhisidenticalbrother.Givenequalopportunities,thetwins,havingidenticalbrains,

wouldhavetestedatroughlythesamelevel.

11.Thisselectioncanbestbetitled____________.

A.MeasuringYourIntelligence

B.IntelligenceandEnvironment

C.TheCaseofPeterandMark

D.HowtheBrainInfluencesIntelligence

12.Thebeststatementofthemainideaofthispassageisthat_______.

A.humanbrainsdifferconsiderably

B.thebrainapersonisbornwithisimportantindetermininghisintelligence

C.environmentiscrucialindeterminingaperson'sintelligence

D.personshavingidenticalbrainswillhaveroughlythesameintelligence

13.Accordingtothepassage,theaverageI.Q.is_______.

A.85.B.100C.110D.125

14.Thecasehistoryofthetwinsappearstosupporttheconclusionthat_______.

A.individualswithidenticalbrainsseldomtestatthesamelevelB.anindividual'sintelligenceisdeterminedonlybyhisenvironment

C.lackofopportunityblocksthegrowthofintelligence

D.changesofenvironmentproducechangesinthestructureofthebrain

15.Thispassagesuggeststhatanindividual'sI.Q._______.

A.canbepredictedatbirth

B.staysthesamethroughouthislife

C.canbeincreasedbyeducation

D.isdeterminedbyhischildhood

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