how a boat is lifted on the答案.docx
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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
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