大学英语六级改革适用（阅读）模拟试卷240

大学英语六级改革适用（阅读）模拟试

卷240

一、长篇阅读（本题共30题，每题7.0分，共30分。）

Tsunamis[A]UpuntilDecemberof2004,thephenomenonoftsunamiwasnotonthe

mindsofmostoftheworld'spopulation.ThatchangedonthemorningofDecember24,

2004whenanearthquakeofmomentmagnitude9.1occurredalongtheoceanictrenchoff

thecoastofSumatrainIndonesia.Thislargeearthquakeresultedinverticaldisplacement

oftheseafloorandgeneratedatsunamithateventuallykilled280,000peopleand

affectedthelivesofseveralmillionpeople.|B]Althoughpeoplelivingonthecoastline

neartheepicenteroftheearthquakehadlittletimeorwarningoftheapproaching

tsunami,thoselivingfartherawayalongthecoastsofThailand,SriLanka,India,and

EastAfricahadplentyoftimetomovetohighergroundtoescape.[C]But,therewasno

tsunamiwarningsysteminplaceintheIndianOcean,andalthoughothertsunami

warningcentersattemptedtoprovideawarning,therewasnoeffectivecommunication

systeminplace.Unfortunately,ithastakenadisasterofgreatmagnitudetopointoulthe

failingsoftheworld'sscientificcommunityandtoeducatealmosteverypersononthe

planetabouttsunami.HowTsunamisAreGenerated[D|Thereisanaverageoftwo

destructivetsunamisperyearinthePacificbasin.Pacificwidetsunamisarearare

phenomenon,occurringevery10-12yearsontheaverage.Mostofthesetsunamisare

generatedbyearthquakesthatcausedisplacementofthsseafloor.[E]Earthquakescause

tsunamibycausingadisturbanceoftheseafloor.Thus,earthquakesthatoccuralong

coastlinesoranywherebeneaththeoceanscangeneratetsunami.Thesizeofthetsunami

isusuallyrelatedtothesizeoftheearthquake,withlargertsunamigeneratedbylarger

earthquakes.（F]Butthesenseofdisplacementisalsoimportant.Tsunamisaregenerally

onlyformedwhenanearthquakecausesverticaldisplacementoftheseafloor.The1906

earthquakenearSanFranciscoCaliforniahadaRichterMagnitudeofabout7.1,yetno

tsunamiwasgeneratedbecausethemotiononthefault（断层）wasstrike-slip,motion

withnoverticaldisplacement.Thus,tsunamisonlyoccursifthefaultgeneratingthe

earthquakehasnormalorreversedisplacement.|G]Becauseofthis,mosttsunamisare

generatedbyearthquakesthatoccuralongthesubductionboundariesofplates,alongthe

oceanictrenches.SincethePacificOceanissurroundedbyplateboundariesofthistype,

tsunamisarefrequentlygeneratedbyearthquakesaroundthemarginsofthePacific

Ocean.ExamplesofTsunamisGeneratedbyEarthquakes[H]May22,1960—Amoment

magnitude9.5earthquakeoccurredalongthesubductionzoneoffSouthAmerica.

BecausethepopulationofChileisfamiliarwithearthquakesandpotentialtsunamis,most

peoplealongthecoastmovedtohigherground.15minutesaftertheearthquake,a

tsunamiwitharun-upof4.5mhitthecoast.Thefirstwavethenretreated,dragging

brokenhousesandboatsbackintotheocean.Manypeoplesawthissmoothretreatofthe

seaasasigntheycouldridetheirboatsouttoseaandrecoversomeofthepropertyswept

awaybythefirstwave.But,about1hourlater,thesecondwavetravelingatavelocityof

166km/hrcrashedinwitharun-upof8m.Thiswavecrushedboatsalongthecoastand

destroyedcoastalbuildings.Thiswasfollowedbyathirdwavetravelingatonly83km/hr

thatcrashedinlaterwitharun-upof11m,destroyingallthatwasleftofcoastalvillages.

Theresultingcausalitieslisted909deadwith834missing.|I|However,thesituationwas

quitedifferentinHawaii.Atsunamiwarningsystemhadbeeninplaceandthetsunami

wasexpectedtoarriveat9:57AM.Ithitat9:58AMand61peopledied,mostly

sightseersthatwantedtowatchthewaverollinatcloserange(obviouslytheyweretoo

close).ThetsunamicontinuedacrossthePacificOcean,eventuallyreachingJapanwhere

itkilledanadditional185people.[J]Anotherexample.OnMarch11,2011amoment

magnitude9.0earthquakestruckoffthenortherncoastofJapan.Theearthquake

generatedatsunamithatroseupto135feetabovesealevelandkilledover20,000

people.Besidesthathighdeathtoll,thetsunamicausedoneoftheworstnucleardisasters

inhistory.TheFukushimanuclearpowerplant,locatedonthecoastwashitbya49feet

tsunamiwavethatovertoppedthetsunamiprotectionwallsthatwereonly19feethigh,

andfloodedthebackupgeneratorstortheplantthatweresomehowplacedonthefirst

floorinaknowntsunamizone!PredictionandEarlyWarning[K]Forareaslocatedat

greatdistancesfromearthquakesthatcouldpotentiallygenerateatsunamithereisusually

plentyoftimeforwarningstobesentandcoastalareasevacuated,eventhoughtsunami

travelsathighvelocitiesacrosstheoceans.Hawaiiisagoodexampleofanarealocated

farfrommostofthesourcesoftsunami,whereearlywarningispossibleandhassaved

lives.ForearthquakesoccurringanywhereonthesubductionmarginsofthePacific

Oceanthereisaminimumof4hoursofwarningbeforeatsunamiwouldstrikeanyofthe

HawaiianIslands.[L]TheNationalOceanicandAtmosphericAdministration(NOAA)

hassetupaPacificwarningsystemforareasinthePacificOcean,calledthePacific

TsunamiWarningCenter.Itconsistsofaninternationalnetworkofseismographic

stations,andtidalstationsaroundthePacificbasinthatcanallsendinformationvia

satellitetotheCenterlocatedinHawaii.[M]Whenanearthquakeoccurssomewherein

theregion,theCenterimmediatelybeginstoanalyzethedatalookingforsignsthatthe

earthquakecouldhavegeneratedatsunami.Thetidalsiationsarealsomonitored,andifa

tsunamiisdetected,awarningissentouttoallareasonthePacificcoast.Ittakesatleast

1hourtoassimilatealloftheinformationandissueawarning.Thusforanaverage

velocityofatsunamiof750km/hr,theregionalsystemcanprovideawarningsufficient

foradequateevacuationofcoastalareaswithin750kmoftheearthquake.[N]Inorderto

beabletoissuewarningsabouttsunamigeneratedwithin100to750kmofan

earthquake,severalregionalwarningcentershavebeensetupinareaspronetotsunami

generatingearthquakes.TheseincludecentersinJapan.Kamchatka,Alaska,Hawaii,

FrenchPolynesia,andChile.Thesesystemshavebeenverysuccessfulatsavinglives.

Forexample,beforetheJapanesewarningsystemwasestablished,14tsunamiskilled

over6000peopleinJapan.Sincetheestablishmentofthewarningsystem20tsunamis

havekilled215peopleinJapan.|O]likeallwarningsystems,theeffectivenessof

tsunamiearlywarningdependsstronglyonlocalauthority'sabilitytodeterminethatthere

isadanger,theirabilitytospreadtheinformationtothosepotentiallyaffected,andonthe

educationofthepublictoheedthewarningsandremovethemselvesfromthearea.

1、Pacificwidetsunamisoccuronceevery10-12yearsaveragely.

标准答案：D'

知识点解析：根据Pacificwidetsunamis和every10-12years定位至UD段。第2句提

到，波及到整个太平洋的海啸很少见，平均大约每隔10-12年发生一次。本题句子

的averagely对应原文的ontheaverageo

2、ComparedwithJapan,fewerpeoplewerekilledinHawaiibythe1960tsunami.

标准答案：I

知识点解析：根据Japan,Hawaii和I960定位到I段。在I960年的海啸中，夏威

夷建有海啸预警系统。只有61人死亡；随后海啸越过太平洋，造成日本185人死

亡。通过两个数据可知夏威夷死亡人数较少。本题句子概括了该段落的内容。

3、Tsunamiwarningsystemshaven'tbeensetupwhenthetsunamiintheIndianOcean

occurred.

标准答案：C

知识点解析：根据warningsystems和IndianOcean定位至UC段。文中提到，当时

的印度洋没有海啸预警机制。题目中的haven"beensetup对应原文的no...in

placeo

4、Thetsunamiin2011notonlykilledmanypeoplebutalsocausedaterriblenuclear

disaster.

标准答案：J

知识点解析：根据2011和nucleardisaster定位到J段。文中提到,2011年日本的

大海啸造成了居高的死亡人数，还导致了历史上最严重的核灾难之一。本题句子的

killedmanypeople与原文的highdeathtoll对应，terrible对应原文的oneofthe

worsto

5、Somepeoplemistakenlythoughtthatthetsunamihadretreatedandwentouttoseain

hopeofretrievingproperty.

标准答案：H

知识点解析；根据retreated和retrievingproperty定位到H段。该段第4、6句提到

在I960年的南美海啸中，很多人把海水的第一次退却看做是可以乘船下海搜寻一

些被第一股海浪卷入海中的财物的机会。本题是对原文的同义转述，题目中的

retrieving与原文的recover对应。

6、Ittakesatleastonehourforthetsunamiwarningcentertoanalyzeallofthe

informationandissueawarning.

标准答案：M

知识点解析:根据warningcenter,alloftheinformation和issueawarning定位到M

段。该段第3句说.把所有讯息统合好并发出预警信号至少需要一个小时。本题句

子的analyze对应原文的assimilateo

7、Thescaleofthetsunamiisusuallydeterminedbythesizeoftheearthquakethat

causesit.

标准答案：E

知识点解析:根据thesizeoftheearthquake定位到E段。该段末句提到，海啸的规

模总是与地震的规模相联系，地震强度越大，海啸的级别越高。本题句子的scale

与原文的size对应，isusuallydeterminedby对应原文的isusuallyrelatedto。

8、ThePacificOceanissurroundedbysubductionboundariesofplates,sotsunamisare

oftencausedbyearthquakesthere.

标准答案：G

知识点解析：根据issurroundedby和subductionboundariesofplates定位到G段。

该段末句说，太平洋正是被这种类型的板块交界处所环绕，所以在太平洋周边发生

地震时常常引发海啸。”这种类型的板块交界处''指的就是大陆板块潜没的交界处。

题目表述与原文相符。

9、Toagreatextent,thelocalgovernmentalsoplaysanimportantroleintheearly

warningofatsunami.

标准答案：0

知识点解析：根据ihelocalgovernmeni定位到。段。该段提到，海啸早期预警的

有效性极大依赖于地方当局判断危险的能力、传播信息的能力等。本题句子是对该

段的概括。

10、Tsunamiwarningcentershavebeenestablishedinseveralcountrieswhere

earthquakestendtogeneratetsunamis.

标准答案：N'

知识点解析：根据题目内容定位到N段。该段提到，为了能给离地震100至750

公里范围的地区发布海啸警报。人们在容易因地震引发海啸的地方建立了几个本地

预警中心。本题句子中的established与原文的setup对应，where

earthquake...tsunami与原文inareaspronetotsunamigeneratingearthquakes意思相

同。

SouthAfricaSafariTopFiveNationalParksandGameReserves[A]ASouthAfrica

safari（游猎）istheidealwildlifetriptogoonbecausetheinfrastructureand

accommodationissuperbinallthewildlifeparksthereanditisstillhighlyaffordablein

comparisontootherAfricancountries.Butgivenachoicesomeofthenationalparksand

gamereservesarebetterthanothers.Hereisatopfivelistrankingthemaccordingto

travelreportsreceivedattheAfricanSafariJournalswebsite,mysafariexperienceof

twentyplusyears,industryforums,magazinesandthegeneralconsensusoftheexperts.

KrugerNationalPark[B]TheKrugerNationalParkhastorankasoneofthebestSouth

Africasafaridestinations,onlyslightlybehindtheMasaiMaraandSerengetiwhenit

comestowildlifeviewingbecausethevegetationinKingercanbedenseandsometimes

impairtheabilitytoseelongerdistances.Butthevarietyofanimals,birdsand

ecosystemsthatyoucanexperiencehereareunparalleledanywhereelseinAfricaandthe

accommodation,roadsandfacilitiesaretopnotchandallataveryaffordableprice.|C]

It'snotunusualtoseelion,leopard,cheetah,apackofwilddog,rhino,elephant,buffalo

andawholehostofantelope,crocodileandhippointhecourseofasingletripincluding

avarietyofinsectsandreptiles.Onthebirdfrontyouwillbespoiledwithaseemingly

never-endingsupplyofeagles,hawks,waterbirdsandahostofmigratoryandindigenous

speciestothetuncofabout510differentvarieties.[D]Youcaneasilydoaselfdrive

safarihereandstillseeadecentamountofwildlifeespeciallyifyousticktothecentral

andsouthernportionsof（hismassivepark（largerthanIreland）.Thenorthhasfewer

animalsduetodryerconditionsbutalsofewertouristswhichmakesforamoreisolated

andintimatewildlifeexperience.IfvarietyisthespiceoflifethenaSouthAfricasafari

intheKrugerNationalParkisarichdishindeed.SabiSandsGameReserve[E]Sharinga

fencelessborderonthewesternsideoftheKrugerNationalParkistheSabiSandsgame

（猎物）reservewhichhasanumberofworldfamousprivateconcessionslikeMalaMala,

SabiSabiandLondelozi.|F]Theremovalofthefencebetweenthetwoparksallowsthe

animalstomovearoundfreelyandthegameviewingexperienceisjustasintheKruger

Nationalwithoneimportantdifference.Becausethisreserveisprivatelyheld,offroad

gametrackingisallowedwhichimprovesyourchancesoffindingtheelusive（难以找至U

的）bigcats,elephant,rhino,buffaloandwilddogtoalargedegree.Theyalsomakeuse

oftwowayradiosineachsafarivehiclesothatifonefndssomethingnoteworthyths

otherscanbealerted.[G]Thesandandsabiriverswhichbisectthereserveprovidethe

focalpointwhichattractsthewildlifetotheareaespeciallyinthedryseason.Soviewing

thebigcatsonaSouthAfricasafarihereisvirtuallyguaranteedandtheaccommodation

issomeofthebestintheworldasillustratedbytheSingitalodgewhichwasthefirstand

onlyaccommodationinthehistoryoftheCondeNastGoldListReaderPolltogeta

perfect100score,anhonourithasheldforthreeyears.Thereareaboutthirtydifferent

lopclasslodgessituatedinthereserve.[H]Butthisallcomesatapriceandunlessyou

havereasonablydeeppockets,thisfantasticreservewillbeoutofreachwhichiswhyit

doesn'tgettheNo.onerankingforSouthAfricasafarinationalparksandreserves.

HluhluweUmfoloziNationalPark[I]Ifyouwanttoseetheendangeredblackandwhite

rhinosinthewildthenthisistheparktoheadforbecausethisiswheretheunstoppable

tidetoextinctionforthewhiterhinoinSouthernAfricawasstemmed（遏制）.Itnow

boaststhelargestpopulationofwhilerhinointheworldnumberingover1,600andalsoa

slowlyincreasingpopulationofblackrhinoatjustover400.[J]OnaSouthAfricasafari

hereyouwillalsobeabletoseelion,leopard,buffalo,elephantandcheetahinthispark

andmorethan400birdspecieshavebeenrecorded.Duetothelargenumberofresident

elephantsyoumighthavesomecloseencounterswiththemontheroadsastheycrossin

frontofyou.Youcangoforadailywalkintheparkinthecompanyofanarmedranger

oryoucandoaseveraldayextendedhikeinthesouthernUmfoloziportion.Madikvve

GameReserve[K]ThisisalatterdayNoah'sarkstorybecausemostofthewildlife

containedinthisparkwasrelocatedherefromotherareasin1991.Twentyseven

differentspeciesamountingtoover10,000headofgamewerere-introducedintothis

areawheretheyoncethrivedbuthaddisappearedbecauseofhuntingandhabitat

destruction.AhugeadvantageoftakingaSouthAfricasafariinthisparkisthatitisnot

situatedinamalariaareasoyoudon'thavetobotherabouttakingmalariatabletsasyou

doinmostotherreserves.[L]Allofthebigfiveareonviewhereaswellascheetahand

therarewilddogpackswhicharethestarsoftheshowherebeingregularlysighted

patrollingtheirhugeterritories.Yourchancesofseeingthemseemtobebetterherethan

mostotherparks.Rareantelopeliketheeland,gemsbokandsableputinanappearance

heretooandyouwillbeabletoenjoyyourwildlifeviewinginrelativepeaceand

isolationbecausenotmanytouristsknowaboutthisexcellentgamereserve.Kgalagadi

TransfrontierPark[M]Thelocalsknowthatthisisanexcellentgameparkanditfalls

intothat"bestkeptsecret'categorythateachcountryseemstohavewhereforsome

unknownreasonareservedoesn'tgetthenoticefromtouristsandsafaricompaniesthatit

deserves.Maybeit'sbecausethisreserveissetintheKalaharidesertandpeopledont

normallyassociatedesertswithlotsofwildlifebuttherearealwaysexceptionstotherule

andthisSouthAfricasafariparkqualifies.[N]Youcanseesomeprettyspecialisedand

veryinterestinggameheresuchasthegemsbokantelopewhichcangoformonths

withoutwater,springbok,bluewildebeest,elandandredhartebeestAndwhereverthere

isagoodsupplyofantelope,thepredatorsareneverfarawaysuchastheblackmaned

lionswhichthisareahasadisproportionatesupplyoff,leopardandcheetahwhichcan

makefulluseofthewideopenspacestochasetheirpreyattopspeed.|O]Themeerkat

(suricate)isalsoregularlyseenhereandbatearedfoxescontributetothescavenging

duties.ThisSouthAfricaparkisfamousforbirdsofpreysuchasthepygmyfalconand

thesociableweaverwhichbuildsnestswhicharethebirdequivalentofapartmentblocks

thataresometimessobigtheybreakthebranchestheyreston.[P]Therearehundredsof

companiesofferingsafaritripstoSouthAfrica.ThisTopSafariinSouthAfricaoperators

listhelpsyouchooseeffectivelybetweenthem.SouthAfricasafaritripreportsgiveyoua

greatideaofwhattoexpectfromatriplikethisbylearningfromotherpeoplestravel

experiences.

11、WhentouristswanttohaveadailywalkinthePark,theymustbeescortedbyan

armedranger.

标准答案：J

知识点解析：根据adailywalk和anarmedranger可查找到J段末句。该句子前半

句提到，你可以在一位带有武器的巡逻员的陪同下每天在公园散步，言下之意，散

步的前提条件就是必须有巡逻员陪同。题目中的beescortedbyallarmedranger是

对原文inthecompanyofanarmedranger的同义改写。

12、TouristscancloselyexperiencewildlifeinthenorthernpartofthePark,because

touriststherearecomparativelyfew.

标准答案：D

知识点解析：根据closelyexperiencewildlife»northernpart等词查找到D段。该段

第2句讲到，因为干旱的气候条件，北部的动物要少一些，这里的游客也相对较

少，因此有利于更亲密地体验偏远的野生生物。题目是对该句子的同义转述，其中

closelyexperiencewildlife对应原文的amore...intimatewildlifeexperienceo

13、Touristsareallowedtotrackthewildgameoffroadinthegamereserveinthatitis

privatelyowned.

标准答案：F

知识点解析：根据trackthewildgameoffroad和privatelyowned查找至UF段第2

句。该句子讲到，由于保护区属于私人拥有，所以允许游客离开道路追踪动物。题

目是对该句子主干的同义改写，其中的thegamereserve是指SabiSandsgame

reservec

14、Owingtoitsdensevegetation,theParkgetsalittlebehindinwildlifewatching.

标准答案：B

知识点解析：根据densevegetation和wildlifewatching等词查找到B段。题目中的

thePark就是指TheKrugerNationalPark。B段首句指出，鲁格国家公园应该被列

为最佳南非旅行目的地之一，但就野生生物景观而言，稍逊于马萨伊玛拉(Masai

Mara)和塞伦盖蒂(Serengeli),因为克鲁格国家公园的植被很浓密。有时会阻碍人们

向远处观望。题H是对该句子的概括，alittlebehind对应原文的slightlybchindo

15、Thesandandsabiriversaretheperfectlocationforviewingthebigcatsbecausea

lotofwildanimalscomehereespeciallyinthedryseason.

标准答案：G

知识点解析：根据sandandsabirivers,viewingthebigcats等词查找到G段。该段

前两句讲到，沙滩以及将塞比保护区分成两块的塞比河流是一个重点地带，它把野

生动物吸引过来，尤其是在旱季，这绝对保证你在这里进行南非旅行时能观赏大型

猫科动物。题0是对原文的同义转述，其中aperfectlocation对应原文的【hefocal

pointo

16、Gemsbokisonekindofspecializedandinterestingantelopesbecauseitcangofor

monthswithoutwater.

标准答案：N

知识点解析：根据关键词Gemsbok和goformonthswithoutwater查找至ljN段。该

段首句便指出，游客在Kgalagadi境外公园可以看到一些特殊而十分有趣的野生动

物，譬如能几个月不喝水而生存下来的南非大羚羊等。可见，南非大羚羊就是一种

特殊而十分有趣的野生动物。题目与原文该句子意思相符。

17、ThelargestpopulationofwhiterhinointheworldcanbefoundintheParkwhere

theextinctionofthewhiterhinowaschecked.

标准答案：I

知识点解析:根据largestpopulation,whiterhino和extinction可查找到I段。该段

提到，如果想在野外看到濒临灭绝的黑、白色犀牛，HluhhweUmfolozi国家公园是

应该前往的地方，因为正是在这里南非犀牛的无情的灭种浪潮受到了遏制，该公园

号称拥有世界上最大数量的白色犀牛，数目超过1600头。本题句子意思与原文一

致。

18、TouristsarenotrequiredtotaketabletstopreventmalariawhenvisitingthePark.

标准答案：K-

知识点解析：根据taketablets和preventmalaria直接查找到K段末句。该句子指

出，Madikwe野生动物保护区极大的好处是它的位置不在疟疾区域范围。因此不必

像在其他保护区那样需要吃疟疾药片。本题句子中的arenotrequiredtotaketablets

对应原文的don'thavetobotherabouttakingmalariatablets0

19、Manywell-knownprivateconcessionsarelocatedinthegamereserve,which

borderswiththeKrugerNationalPark.

标准答案：E」

知识点解析：根据privateconcessions,located和borderswith等词可查找到E段。

该段讲到，克鲁格国家公园的西边与塞比沙滩野生动物保护区共同拥有一条不设栅

栏的边界。保护区内有许多世界著名的私人拥有的区域，如MalaMala,SabiSabi

和Londelozi。可见，题目中的gamereserve就是指SabiSandsgamereserve,其中

的...privateconcessionsarelocatedin…同义改写了原文which引导的定语从句。而

borderswith则与段首的Sharingafencelessborder相对应。

20、ThereasonwhytheParkdoesn'tgetenoughattentionfromtouristsandsafari

companiesmightbethatitissituatedindesert.

标准答案：M

知识点解析:根据doesn'tgetenoughattention和situatedinthedesert查找到M段。

该段首句末尾提到，因为某种未知的原因，这个野生动物保护区没有得到游人和旅

行公司应该给予的关注：随后乂补充道“原因可能是这个野生动物保护区位于非洲

南部的喀拉哈里沙漠”。题目正是对这两句话的概括。

RenewableEnergy|A|Inthepastcentury,ithasbeenseenthattheconsumptionofnon­

renewablesourcesofenergyhascausedmoreenvironmentaldamagethananyother

humanactivity.Electricitygeneratedfromfossilfuelssuchascoalandcrudeoilhasled

tohighconcentrationsofharmfulgasesintheatmosphere.Thishasinturnledtomany

problemsbeingfacedtodaysuchasozonedepletionandglobalwarming.Vehicular

pollutionhasalsobeenamajorproblem.[B]Therefore,alternativesourcesofenergy

havebecomeveryimportantandrelevanttotoday'sworld.Thesesources,suchasthesun

andwind,canneverbeexhaustedandthereforearecalledrenewable.Theycauseless

emissionandareavailablelocally.Theirusecan,toalargeextent,reducechemical,

radioactive,andthermalpollution.Theystandoutasaviablesourceofcleanand

limitlessenergy.Thesearealsoknownasnon-conventionalsourcesofenergy.The

followingsectionoutlinesseveraldifferenttypesofrenewableenergy.[C]Solarenergy

isthemostreadilyavailablesourceofenergy.Itdoesnotbelongtoanybodyandis,

therefore,free.Itisalsothemostimportantofthenon-conventionalsourcesofenergy

becauseitisnon-pollutingand,therefore,helpsinlesseningthegreenhouseeffect.|D]

Solarenergyhasbeenusedsinceprehistorictimes,butinamostprimitivemanner.

Before1970,someresearchanddevelopmentwascarriedoutinafewcountriesto

exploitsolarenergymoreefficiently,butmostofthisworkremainedmainlyacademic.

Afterthedramaticriseinoilpricesinthe1970s,severalcountriesbegantoformulate

extensiveresearchanddevelopmentprogrammestoexploitsolarenergy.[E]Whenwe

hangoutourclothestodryinthesun,weusetheenergyofthesun.Inthesameway,

solarpanelsabsorbtheenergyofthesuntoprovideheatforcookingandfbrheating

water.Suchsystemsareavailableinthemarketandarebeingusedinhomesand

factories.Solarenergycanalsobeusedtomeetourelectricityrequirements.Through

SolarPhotovoltaic(SPV)cells,solarradiationgetsconvertedintoDCelectricitydirectly.

Thiselectricitycaneitherbeusedasitisorcanbestoredinthebattery.Thisstored

electricalenergythencanbeusedatnight.[F]Anothertypeofrenewableenergyishydro

power.Itisoneofthebest,cheapest,andcleanestsourcesofenergy,although,withbig

dams,therearemanyenvironmentalandsocialproblems.Smalldamsare,however,free

fromtheseproblems.Thisisinfactoneoftheearliestknownrenewableenergysources,

inthecountry(sincethebeginningofthe20thcentury).Infact,forthelastfewhundred

years,peoplelivinginthehillsoftheHimalayashavebeenusingwatermills,orchakki,

togrindwheatBesidesbeingfreefromtheproblemofpollution,smallhydropowerplants

arealsofreefromissuesandcontroversiesthatareassociatedwiththebiggerprojects,

namelyaffectingthelivesofthousandsofpeoplelivingalongthebanksoftherivers,

destructionoflargeareasunderforest,andseismologicalthreats.[G]Newenvironmental

lawsaffectedbythedangerofglobalwanninghavemadeenergyfromsmallhydropower

plantsmorerelevant.Thesesmallhydropowerplantscanservetheenergyneedsof

remoteruralareasindependently.Therealchallengeinaremotearealiesinsuccessful

marketingoftheenergyandrecoveringthedues.Localindustriesshouldbeencouraged

tousethiselectricityfbrsustainabledevelopmentItisatechnologywithenormous

potential,whichcouldexploitthewaterresourcestosupplyenergytoremoteruralareas

withlittleaccesstoconventionalenergysources.Italsoeliminatesmostofthenegative

environmentaleffectsassociatedwithlargehydroprojects.[H]Theseacouldalso

provideimmensepower—thatisoceanthermal,tidalandwaveenergy.Onanaverage,

the60millionsquarekilometreofthetropicalseasabsorbsolarradiationequivalentto

theheatcontentof245billionbarrelsofoil.Scientistsfeelthatifthisenergycanbe

tappedalargesourceofenergywillbeavailabletothetropicalcountriesandtoother

countriesaswell.TheprocessofharnessingthisenergyiscalledOTEC(oceanthermal

energyconversion).Itusesthetemperaturedifferencesbetweenthesurfaceoftheocean

andthedepthsofabout1000mtooperateaheatengine,whichproduceselectricpower.

[I]Energyisalsoobtainedfromwavesandtides.InsomecountriessuchasJapansmall

scalepowergeneratorsrunbyenergyfromwavesofthsocean,havebeenusedaspower

sourcesfbrchannelmarkingbuoys.[J]Anotherrenewableenergyresourceisbiomass

whichisderivedfromthecarbonaceouswasteofvarioushumanandnaturalactivities.It

isderivedfromnumeroussources,includingtheby-productsfromthetimberindustry,

agriculturalcrops,rawmaterialfromtheforest,majorpartsofhouseholdwasteand

wood.[K]Biomassdoesnotaddcarbondioxidetotheatmosphereasitabsorbsthesame

amountofcarboningrowingasitreleaseswhenconsumedasafuel.Itsadvantageisthat

itcanbeusedtogenerateelectricitywiththesameequipmentofpowerplantsthatare

nowburningfossilfuels.Biomassisanimportantsourceofenergyandthemost

importantfuelworldwideaftercoal,oilandnaturalgas.|L]Traditionaluseofbiomassis

morethanitsuseinmodernapplication.Inthedevelopedworldbiomassisagain

becomingimportantforapplicationssuchascombinedheatandpowergeneration.In

addition,biomassenergyisgainingsignificanceasasourceofcleanheatfordomestic

heatingandcommunityheatingapplications.InfactincountrieslikeFinland,USAand

SwedenthepercapitabiomassenergyusedishigherthanitisinIndia,ChinaorinAsia

[M]Thecategoryofrenewableenergyshouldalsoincludegeothermalenergy.Welive

betweentwogreatsourcesofenergy,thehotrocksbeneaththesurfaceoftheearthand

thesuninthesky.Ourancestorsknewthevalueofgeothermalenergy;theybathedand

cookedinhotsprings.Todaywehaverecognizedthatthisresourcehaspotentialfor

muchbroaderapplication.[N]Thecoreoftheearthisveryhotanditispossibletomake

useofthisgeothermalenergy(inGreekitmeansheatfromtheearth).Theseareareas

wheretherearevolcanoes,hotsprings,andgeysers,andmethaneunderthewaterinthe

oceansandseas.Insomecountries,suchasintheUSAwaterispumpedfrom

undergroundhotwaterdepositsandusedtoheatpeople'shouses.[O]Theutilizationof

geothermalenergyfortheproductionofelectricitydatesbacktotheearlypartofthe

twentiethccmury.For50ye