Unit-4-water-cycle

Unit4Wateris…Theonlycommonsubstancethatexistsasasolid,aliquid,andagas.PresenteverywhereonEarth.Inacontinuousstateofchangeandmovement.OurEarthismostlywaterApproximately70%oftheEarth’ssurfaceiswater30%oftheEarth’ssurfaceislandGlaciers冰川TheWaterCycleWater,whichcoversthemajorityoftheEarth’ssurface(thehydrosphere),circulatesthroughthecrust,oceans,andatmosphereinwhatisknownasthewatercycle.Evaporation:Evaporationiswhenthesunheatsupwaterinriversorlakesortheoceanandturnsitintovapourorsteam.Thewatervapourorsteamleavestheriver,lakeoroceanandgoesintotheair.Condensation[,kɑndɛn'seʃən]凝结Watervapourintheairgetscoldandchangesbackintoliquid,formingclouds.Thisiscalledcondensation.Precipitation:Precipitationoccurswhensomuchwaterhascondensedthattheaircannotholditanymore.Thecloudsgetheavyandwaterfallsbacktotheearthintheformofrain,hail,sleetorsnow.AftertheprecipitationWatercantakedifferentroutes:EvaporateGroundWaterSoilMoisture土壤水SurfacerunoffCollection:Whenwaterfallsbacktoearthasprecipitation,itmayfallbackintheoceans,lakesorriversoritmayenduponland.Whenitendsuponland,itwilleithersoakintotheearthandbecomepartofthe“groundwater”thatplantsandanimalsusetodrinkoritmayrunoverthesoilandcollectintheoceans,lakesorriverswherethecyclestartsTranspiration[,trænspɪ'reʃən]istheevaporationofwaterfromaplant'sleaves,stem,orflowers.蒸腾作用Book2-Unit4TheWaterCycle(alsoknownasthehydrologiccycle)isthejourneywatertakesasitcirculatesfromthelandtotheskyandbackagain.TheSun'sheatprovidesenergytoevaporatewaterfromtheEarth'ssurface(oceans,lakes,etc.).Plantsalsolosewatertotheair(thisiscalledtranspiration).Thewatervaporeventuallycondenses,formingtinydropletsinclouds.Whenthecloudsmeetcoolairoverland,precipitation(rain,sleet,orsnow)istriggered,andwaterreturnstotheland(orsea).Someoftheprecipitationsoaksintotheground.Someoftheundergroundwateristrappedbetweenrockorclaylayers;thisiscalledgroundwater.Butmostofthewaterflowsdownhillasrunoff(abovegroundorunderground),eventuallyreturningtotheseasasslightlysaltywater.UnevendistributionofwaterresourcesTheplanet’swaterbudget.Onlyatinyfractionbyvolumeoftheworld’swatersupplyisfreshwateravailableforhumanuse.Question：howcanwewastelesswaterinindustry,homes,andbusiness?Copynature,raiseprices,improveefficiencyWecansavewaterbyusingyardplantsthatneedlittlewater,usingdripirrigation,raisingwaterprices,fixingleaks,andusingwater-savingtoiletsandotherappliance.AmoresustainablewaterfutureReducewastewater:wewasteabouttwo-thirdsofthewaterweusebutusingwatermoreefficientlycouldreducewastagetoabout15%.About60%oftheworld’sirrigationwateriswasted,butseveralirrigationtechniquecouldreducesthewasteto5-20%.PartIBook2-Unit4CommunicativeActivitiesYoumayexpressuncertaintylikethis:Youmayexpresscertaintylikethis:I’mnotquitesure...I’msureI’llbeverymuchinterestedinreadingyourarticle.MoreExpressionsforCertainty&UncertaintyBook2-Unit12•I’mquitesure/certain(that)…•I’mabsolutelysure/certain(that)…•I’mfairlysure/certain(that)…•I’msure/certainabout…•I’venodoubtabout…•Yes,I’monehundredpercentsure.•Yes,certainly/definitely/ofcourse.•Yes,withoutdoubt.•Yes,really!•Yes,that’sobvious.Book2-Unit12Howtoexpresscertainty:Howtoexpressuncertainty:•Well,it’spossibleIsuppose,butI’mnotreallysure.•Well,itmightbe,butIdoubtit.•Well,there’salwaysachance,butIhavemydoubts.•Sorry,I’mnotsure.•Ican’tmakeupmymindwhethertodo…•Ican’tdecide…•I’mnotreally/toosureabout…•I’moftwomindsabout…•Ican’tsayforcertain.•Iwouldn’tbetoosureabout…Book2-Unit12Extraexpressionsofthesamefunctions:-Idon’tthinktherecanbeanydoubtabout/asto…-Thereisno/verylittledoubtinmymindabout/asto…-It’s/That’smyconviction…-I’m(quite)convinced…-It’squitecertainthat…Book2-Unit12-I’mafraidIcan’tbecertainabout…-There’ssomedoubtinmymindabout…-I’mnotatallconvinced/certain…-Onecan’tsaywithanycertaintythat…-There’sstillanelementofdoubtabout…DiscussionTheunexpectedalwayshappens.ThemostunexpectedmomentinmylifeLearntounderstandtheculturalimplicationsofthisproverbandtryingtofindexamplesinreallifeinitssupport.Book2-Unit12ThemostunexpectedmomentinmylifeStoryTellingWhenWhereWhoWhatWhyHowResultBook2-Unit4Book2-Unit4WastewatertreatmentPhysical,chemicalandbiologicalprocessesformakingwastewatersuitableforhumanconsumptionandotherpurposes.wastewater99.9%water0.1%wasteWhywastewatertreatment?Listentoalecturegivenbyanexpertaboutwastewatertreatmenttechnologies.Whileyoulisten,takenotesandcompletethetasksonpage51.WastewatertreatmentwatermoleculesWastewatertreatmentplantAnengineeringmarvelSewersystemItconnectsmillionsofhomes,businesses,industries,andinstitutionstoanetworkofundergroundpipeswhichtransportswastewatertothewastewatertreatmentplantbeforeitisreleasedtoariverorlake.ThreemajorstepsWastewatertreatmentplant•Preliminarystep:mechanicalprocessesseparatelargesolids(sand,grit沙砾)anddebris(残渣，废物)fromtheliquid•Primarystep:mechanicalandbiologicalprocessesfurtherseparatewaterfromwastematerials•Secondarystep:chemicalprocesseskillremainingharmfulbacteriaNature’sprocessesofwastewatertreatmentandhowitisdifferentfromtheengineeringprocessesi