how a boat is lifted on the答案.docx

how a boat is lifted on the答案.docx

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howaboatisliftedonthe答案

howaboatisliftedonthe答案

剑桥雅思阅读11原文（test1）

READINGPASSAGE1

Youshouldspendabout20minutesonQuestions1-13,whicharebasedonReadingPassage1below.

Crop-growingskyscrapers

Bytheyear2050,nearly80%oftheEarth’spopulationwillliveinurbancentres.Applyingthemostconservativeestimatestocurrentdemographictrends,thehumanpopulationwillincreasebyaboutthreebillionpeoplebythen.Anestimated109hectaresofnewland（about20%largerthanBrazil）willbeneededtogrowenoughfoodtofeedthem,iftraditionalfarmingmethodscontinueastheyarepractisedtoday.Atpresent,throughouttheworld,over80%ofthelandthatissuitableforraisingcropsisinuse.Historically,some15%ofthathasbeenlaidwastebypoormanagementpractices.Whatcanbedonetoensureenoughfoodfortheworld’spopulationtoliveon?

Theconceptofindoorfarmingisnotnew,sincehothouseproductionoftomatoesandotherproducehasbeeninvogueforsometime.Whatisnewistheurgentneedtoscaleupthistechnologytoaccommodateanotherthreebillionpeople.Manybelieveanentirelynewapproachtoindoorfarmingisrequired,employingcutting-edgetechnologies.Onesuchproposalisforthe‘VerticalFarm’.Theconceptisofmulti-storeybuildingsinwhichfoodcropsaregrowninenvironmentallycontrolledconditions.Situatedintheheartofurbancentres,theywoulddrasticallyreducetheamountoftransportationrequiredtobringfoodtoconsumers.Verticalfarmswouldneedtobeefficient,cheaptoconstructandsafetooperate.Ifsuccessfullyimplemented,proponentsclaim,verticalfarmsofferthepromiseofurbanrenewal,sustainableproductionofasafeandvariedfoodsupply（throughyear-roundproductionofallcrops）,andtheeventualrepairofecosystemsthathavebeensacrificedforhorizontalfarming.

Ittookhumans10,000yearstolearnhowtogrowmostofthecropswenowtakeforgranted.Alongtheway,wedespoiledmostofthelandweworked,oftenturningverdant,naturalecozonesintosemi-ariddeserts.Withinthatsametimeframe,weevolvedintoanurbanspecies,inwhich60%ofthehumanpopulationnowlivesverticallyincities.Thismeansthat,forthemajority,wehumanshaveshelterfromtheelements,yetwesubjectourfood-bearingplantstotherigoursofthegreatoutdoorsandcandonomorethanhopeforagoodweatheryear.However,moreoftenthannotnow,duetoarapidlychangingclimate,thatisnotwhathappens.Massivefloods,longdroughts,hurricanesandseveremonsoonstaketheirtolleachyear,destroyingmillionsoftonsofvaluablecrops.

Thesupportersofverticalfarmingclaimmanypotentialadvantagesforthesystem.Forinstance,cropswouldbeproducedallyearround,astheywouldbekeptinartificiallycontrolled,optimumgrowingconditions.Therewouldbenoweather-relatedcropfailuresduetodroughts,floodsorpests.Allthefoodcouldbegrownorganically,eliminatingtheneedforherbicides,pesticidesandfertilisers.Thesystemwouldgreatlyreducetheincidenceofmanyinfectiousdiseasesthatareacquiredattheagriculturalinterface.Althoughthesystemwouldconsumeenergy,itwouldreturnenergytothegridviamethanegenerationfromcompostingnon-ediblepartsofplants.Itwouldalsodramaticallyreducefossilfueluse,bycuttingouttheneedfortractors,ploughsandshipping.

Amajordrawbackofverticalfarming,however,isthattheplantswouldrequireartificiallight.Withoutit,thoseplantsnearestthewindowswouldbeexposedtomoresunlightandgrowmorequickly,reducingtheefficiencyofthesystem.Single-storeygreenhouseshavethebenefitofnaturaloverheadlight:

evenso,manystillneedartificiallighting.Amulti-storeyfacilitywithnonaturaloverheadlightwouldrequirefarmore.Generatingenoughlightcouldbeprohibitivelyexpensive,unlesscheap,renewableenergyisavailable,andthisappearstoberatherafutureaspirationthanalikelihoodforthenearfuture.

Onevariationonverticalfarmingthathasbeendevelopedistogrowplantsinstackedtraysthatmoveonrails.Movingthetraysallowstheplantstogetenoughsunlight.Thissystemisalreadyinoperation,andworkswellwithinasingle-storeygreenhousewithlightreachingitfromabove:

itisnotcertain,however,thatitcanbemadetoworkwithoutthatoverheadnaturallight.

Verticalfarmingisanattempttoaddresstheundoubtedproblemsthatwefaceinproducingenoughfoodforagrowingpopulation.Atthemoment,though,moreneedstobedonetoreducethedetrimentalimpactitwouldhaveontheenvironment,particularlyasregardstheuseofenergy.Whileitispossiblethatmuchofourfoodwillbegrowninskyscrapersinfuture,mostexpertscurrentlybelieveitisfarmorelikelythatwewillsimplyusethespaceavailableonurbanrooftops.

Questions1-7

Completethesentencesbelow.

ChooseNOMORETHANTWOWORDSfromthepassageforeachanswer.

Writeyouranswersinboxes1-7onyouranswersheet.

Indoorfarming

1Somefoodplants,including__________,arealreadygrownindoors.

2Verticalfarmswouldbelocatedin__________,meaningthattherewouldbelessneedtotakethemlongdistancestocustomers.

3Verticalfarmscouldusemethanefromplantsandanimalstoproduce__________.

4Theconsumptionof__________wouldbecutbecauseagriculturalvehicleswouldbeunnecessary.

5Thefactthatverticalfarmswouldneed__________lightisadisadvantage.

6Oneformofverticalfarminginvolvesplantingin__________whicharenotfixed.

7Themostprobabledevelopmentisthatfoodwillbegrownon__________intownsandcities.

Questions8-13

DothefollowingstatementsagreewiththeinformationgiveninReadingPassage1?

Inboxes8-13onyouranswersheet,write

TRUEifthestatementagreeswiththeinformation

FALSEifthestatementcontradictstheinformation

NOTGIVENifthereisnoinformationonthis

8MethodsforpredictingtheEarth’spopulationhaverecentlychanged.

9Humanbeingsareresponsibleforsomeofthedestructiontofood-producingland.

10Thecropsproducedinverticalfarmswilldependontheseason.

11Somedamagetofoodcropsiscausedbyclimatechange.

12Fertiliserswillbeneededforcertaincropsinverticalfarms.

13Verticalfarmingwillmakeplantslesslikelytobeaffectedbyinfectiousdiseases.

READINGPASSAGE2

Youshouldspendabout20minutesonQuestions14-26,whicharebasedonReadingPassage2below.

THEFALKIRKWHEEL

Auniqueengineeringachievement

TheFalkirkWheelinScotlandistheworld’sfirstandonlyrotatingboatlift.Openedin2002,itiscentraltotheambitious￡84.5mMillenniumLinkprojecttorestorenavigabilityacrossScotlandbyreconnectingthehistoricwaterwaysoftheForth&ClydeandUnionCanals.

ThemajorchallengeoftheprojectlayinthefactthattheForth&ClydeCanalissituated35metresbelowtheleveloftheUnionCanal.Historically,thetwocanalshadbeenjoinednearthetownofFalkirkbyasequenceof11locks—enclosedsectionsofcanalinwhichthewaterlevelcouldberaisedorlowered—thatsteppeddownacrossadistanceof1.5km.Thishadbeendismantledin1933,therebybreakingthelink.Whentheprojectwaslaunchedin1994,theBritishWaterwaysauthoritywerekeentocreateadramatictwenty-first-centurylandmarkwhichwouldnotonlybeafittingcommemorationoftheMillennium,butalsoalastingsymboloftheeconomicregenerationoftheregion.

Numerousideasweresubmittedfortheproject,includingconceptsrangingfromrollingeggstotiltingtanks,fromgiantsee-sawstooverheadmonorails.TheeventualwinnerwasaplanforthehugerotatingsteelboatliftwhichwastobecomeTheFalkirkWheel.Theuniqueshapeofthestructureisclaimedtohavebeeninspiredbyvarioussources,bothmanmadeandnatural,mostnotablyaCelticdouble-headedaxe,butalsothevastturningpropellerofaship,theribcageofawhaleorthespineofafish.

ThevariouspartsofTheFalkirkWheelwereallconstructedandassembled,likeonegianttoybuildingset,atButterleyEngineering’sSteelworksinDerbyshire,some400kmfromFalkirk.Ateamtherecarefullyassembledthe1,200tonnesofsteel,painstakinglyfittingthepiecestogethertoanaccuracyofjust10mmtoensureaperfectfinalfit.Inthesummerof2001,thestructurewasthendismantledandtransportedon35lorriestoFalkirk,beforeallbeingboltedbacktogetheragainontheground,andfinallyliftedintopositioninfivelargesectionsbycrane.TheWheelwouldneedtowithstandimmenseandconstantlychangingstressesasitrotated,sotomakethestructuremorerobust,thesteelsectionswereboltedratherthanweldedtogether.Over45,000boltholeswerematchedwiththeirbolts,andeachboltwashand-tightened.

TheWheelconsistsoftwosetsofopposingaxe-shapedarms,attachedabout25metresaparttoafixedcentralspine.Twodiametricallyopposedwater-filled‘gondolas’,eachwithacapacityof360,000litres,arefittedbetweentheendsofthearms.Thesegondolasalwaysweighthesame,whetherornottheyarecarryingboats.Thisisbecause,accordingtoArchimedes’principleofdisplacement,floatingobjectsdisplacetheirownweightinwater.Sowhenaboatentersagondola,theamountofwaterleavingthegondolaweighsexactlythesameastheboat.ThiskeepstheWheelbalancedandso,despiteitsenormousmass,itrotatesthrough180°infiveandahalfminuteswhileusingverylittlepower.Ittakesjust1.5kilowatt-hours（5.4MJ）ofenergytorotatetheWheel—roughlythesameasboilingeightsmalldomestickettlesofwater.

BoatsneedingtobeliftedupenterthecanalbasinattheleveloftheFort