六级考试阅读与综合题授课文档格式.docx

六级考试阅读与综合题授课文档格式.docx

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Y（forYES）ifthestatementagreeswiththeinformationgiveninthepassage;

N（forNO）ifstatementcontradictstheinformationgiveninthepassage;

NG（forNOTGIVEN）iftheinformationisnotgiveninthepassage.

Forquestions5-10,completethesentenceswiththeinformationgiveninthepassage.

1、样卷

Rainforests

Tropicalrainforestsarethemostdiverseecosystem（生态系统）onEarth,andalsotheoldest.Today,tropicalrainforestscoveronly6percentoftheEarth'

sgroundsurface,buttheyarehometooverhalfoftheplanet'

splantandanimalspecies.

WhatIsaRainforest?

Generallyspeaking,arainforestisanenvironmentthatreceiveshighrainfallandisdominatedbytalltrees.Awiderangeofecosystems（生态系统）fallintothiscategory,ofcourse.Butmostofthetimewhenpeopletalkaboutrainforests,theymeanthetropicalrainforestslocatedneartheequator.

Theseforestsreceivebetween160and400inchesofrainperyear.Thetotalannualrainfallisspreadprettyevenlythroughouttheyear,andthetemperaturerarelydips（微降,下沉）below60degreesFahrenheit.

Thissteadyclimateisduetothepositionofrainforestsontheglobe.Becauseoftheorientation（方向,目标）oftheEarth'

saxis（地球旋转轴[座标系]）,theNorthernandSouthernhemisphereseachspendpartoftheyeartiltedawayfromthesun.Sincerainforestsareatthemiddleoftheglobe,locatedneartheequator,theyarenotespeciallyaffectedbythischange.Theyreceivenearlythesameamountofsunlight,andthereforeheat,allyear.Consequently,theweatherintheseregionsremainsfairlyconstant.

Theconsistentlywet,warmweatherandamplesunlightgiveplantlifeeverythingitneedstothrive.Treeshavetheresourcestogrowtotremendousheights.andtheyliveforhundreds,eventhousands,ofyears.Thesegiants,whichreach60to150ft（英尺（foot,feet））intheair,formthebasicstructureoftherainforest.Theirtopbranchesspreadwideinordertocapturemaximumsunlight.Thiscreatesathickcanopy（树冠）levelatthetopoftheforest,withthinnergreenerylevelsunderneath.Somelargetreesgrowsotallthattheyeventoweroverthecanopylayer.

Asyougolower,downintotherainforest,youfindlessandlessgreenery.Theforestfloorismadeupofmoss,fungi（真菌类<

包括霉菌,食用伞菌,酵母菌等>

）,anddecayingplantmatterthathasfallenfromtheupperlayers.Thereasonforthisdecreaseingreeneryisverysimple：

Theoverabundanceofplantsgatheringsunlightatthetopoftheforestblocksmostsunlightfromreachingthebottomoftheforest,makingitdifficultforrobust（强壮的;

健全的）plantstothrive.

TheForestfortheTrees

Theamplesunlightandextremelywetclimateofmanytropicalareasencouragethegrowthoftoweringtreeswithwidecanopies.Thisthicktoplayeroftherainforestdictates（指示;

指定;

指令）thelivesofallotherplantsintheforest.Newtreeseedlingsrarelysurvivetomakeittothetopunlesssomeoldertreesdie,creatinga"

hole"

inthecanopy.Whenthishappens,alloftheseedlingsonthegroundlevelcompeteintenselytoreachthesunlight.

Manyplantspeciesreachthetopoftheforestbyclimbingthetalltrees.Itismucheasiertoascend（上升,攀登）thisway,becausetheplantdoesn'

thavetoformitsownsupportingstructure.

Someplantspecies,calledepiphytes（附生植物）,growdirectlyonthesurfaceofthegianttrees.Theseplants,whichincludeavarietyoforchidsandferns,makeupmuchoftheunderstory,thelayeroftherainforestrightbelowthecanopy.Epiphytesarecloseenoughtothetoptoreceiveadequatelight,andtherunoff（流走之物）fromthecanopylayerprovidesallthewaterandnutrients（养分）theyneed,whichisimportantsincetheydon'

thaveaccesstothenutrientsintheground.

Stranglers（扼杀者）andButtresses（支撑者）

Someepiphyteseventuallydevelopintostranglers.Theygrowlong,thickrootsthatextenddownthetreetrunkintotheground.Astheycontinuetogrow,therootsformasortofwebstructureallaroundthetree.Atthesametime,thestranglerplant'

sbranchesextendupward,spreadingoutintothecanopy.Eventually,thestranglermayblocksomuchlightfromabove,andabsorbsuchahighpercentageofnutrientsfromthegroundbelow,thatthehosttreedies.

Competitionovernutrientsisalmostasintenseascompetitionforlight.Theexcessiverainfallrapidlydissolves（溶解）nutrientsinthesoil,makingitrelativelyinfertileexceptatthetoplayers.Forthisreason,rainforesttreerootsgrowoutwardtocoverawiderarea,ratherthan（…而不…,与其…倒不如…）downwardtolowerlevels.Thismakesrainforesttreessomewhatunstable,sincetheydon'

thaveverystronganchorsintheground.Sometreescompensateforthisbygrowingnaturalbuttresses.Thesebuttressesarebasicallytreetrunksthatextendoutfromthesideofthetreeanddowntotheground,givingthetreeadditionalsupport.

Rainforesttreesaredependentonbacteriathatarecontinuallyproducingnutrientsintheground.Rainforestbacteriaandtreeshaveaveryclose,symbiotic（共生的）relationship.Thetreesprovidethebacteriawithfood,intheformoffallenleavesandothermaterial,andthebacteriabreakthismaterialdownintothenutrientsthatthetreesneedtosurvive.

Oneofthemostremarkablethingsaboutrainforestplantlifeisitsdiversity.ThetemperaterainforestsofthePacificNorthwestaremainlycomposedofadozenorsotreespecies.Atropicalrainforest,ontheotherhand,mighthave300distincttreespecies.

AllCreatures,GreatandSmall

Rainforestsarehometothemajorityofanimalspeciesintheworld.Andagreatnumberofspecieswhonowliveinotherenvironments,includinghumans,originallyinhabitedtherainforests.Researchersestimatethatinalargerainforestarea,theremaybemorethan10milliondifferentanimalspecies.

Mostofthesespecieshaveadaptedforlifeintheupperlevelsoftherainforest,wherefoodismostplentiful.Insects,whichcaneasilyclimborflyfromtreetotree,makeupthelargestgroup（antsarethemostabundantanimalintherainforest）.Insectspecieshaveahighlysymbioticrelationshipwiththeplantlifeinarainforest.Theinsectsmovefromplanttoplant,enjoyingthewealthoffoodprovidedthere.Astheytravel,theinsectsmaypickuptheplants'

seeds,droppingthemsomedistanceaway.Thishelpstodispersethepopulationoftheplantspeciesoveralargerarea.

Thenumerousbirdsoftherainforestalsoplayamajorpartinseeddispersal.Whentheyeatfruitfromaplant,theseedspassthroughtheirdigestivesystem.Bythetimetheyexcrete（排泄）theseeds,thebirdsmayhaveflownmanymilesawayfromthefruit-bearingtree.

Therearealsoalargenumberofreptilesandmammalsintherainforest.Sincetheweatherissohotandhumidduringtheday,mostrainforestmammalsareactiveonlyatnight,duskordawn.Themanyrainforestbatspeciesareespeciallywelladaptedforthislifestyle.Usingtheirsonar,batsnavigateeasilythroughthemassoftreesintherainforest,feedingoninsectsandfruit.

Whilemostrainforestspeciesspendtheirlivesinthetrees,thereisalsoalotoflifeontheforestfloor.Greatapes,wildpigs,bigcatsandevenelephantscanallbefoundinrainforests.Thereareanumberofpeoplewholiveintherainforests,aswell.Thesetribes---which,upuntilrecently,numberedinthethousands---arebeingforcedoutoftherainforestsatanalarmingratebecauseofdeforestation.

Deforestation

Inthepasthundredyears,humanshavebegundestroyingrainforestsatanalarmingrate.Today,roughly1.5acresofrainforestaredestroyedeverysecond.Peoplearecuttingdowntherainforestsinpursuitofthreemajorresources：

∙Landforcrops

∙Lumber（木材,木料）forpaperandotherwoodproducts

∙Landforlivestock（家畜,牲畜）pastures（牧草地,牧场）

Inthecurrenteconomy,peopleobviouslyhaveaneedforalloftheseresources.Butalmostallexpertsagreethat,overtime,wewillsuffermuchmorefromthedestructionoftherainforeststhanwewillbenefit.

Theworld'

srainforestsareanextremelyvaluablenaturalresource,tobesure,butnotfortheirlumberortheirland.TheyarethemaincradleoflifeonEarth,andtheyholdmillionsofuniquelifeformsthatwehaveyettodiscover.Destroyingtherainforestsiscomparabletodestroyinganunknownplanet---wehavenoideawhatwe'

relosing.Ifdeforestationcontinuesatitscurrentrate,theworld'

stropicalrainforestswillbewipedoutwithin40years.

1.VirtuallyallplantandanimalspeciesonEarthcanbefoundintropicalrainforests.（N）

2.Thereisnotmuchchangeintheweatherinthetropicalrainforestsalltheyearround.（Y）

3.ThelargestnumberofrainforestsintheworldarelocatedontheAfricancontinent.（NG）

4.Belowthecanopylevelofatropicalrainforestgrowsanoverabundanceofplants.（N）

5.Newtreeseedlings（刚出芽的幼苗）willnotsurvivetoreachthecanopylevelunless________.（someoldertreesdie）

6.Epiphytes,whichformmuchoftheunderstoryoftherainforest,getalltheirwaterandnutrientsfrom________.（thecanopylayer）

7.Stranglersaresocalledbecausethey________byblockingthesunlightandcompetingforthenutrients.

（killthehosttree）

8.Sincerainforestbacteriaandtreesdependoneachotherforlife,therelationshiptheyformistermed________.（symbiotic共生的）

9.Plantspeciesaredispersed（被驱散的,被分散的,散布的）overalargeareawiththehelpof________.（insectsandbirds／insects／birds／animals）

10.Aswearestillignorantofmillionsofuniquelifeformsintherainforest,deforestation（森林开伐）canbecomparedto