a dam is a man-made structure built across a river. most dams 阅读理解答案

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1、Adamisaman-madestructurebuiltacrossariver.Mostdams阅读理解答案　　Adamisaman-madestructurebuiltacrossariver.Mostdamsarebuilttocontrolariver’swaterflow,improvenavigationandcontrolflooding.However,somedamsarebuilttoproducehydro-electricpower.　　Hydro-electricpowerisproducedaswaterpassesthroughadam,an

2、dintoariverbelow.Themorewaterthatpassesthroughadam,themoreenergyisproduced.Onceadamisbuilt,aman-madelakeiscreatedbehindthedam.　　Electricityisproducedbyakindofequipmentcalledaturbine(水轮机).Turbinescontainmetalcoils(线圈)surroundedbymagnets(磁铁).Whenthemagnetsmoveroundrapidlyoverthemetalcoils,el

3、ectricityisproduced.Turbinesarelocatedinsidedams.Thefallingwatermakesthemagnetsgoaroundthecoils.　　Damsprovidecleanenergy,buttheycanalsoharmtheenvironment.Speciesthatuseriverstoreproduceareoftenhurtbydams.IntheNorthwestoftheUS,thepopulationoffisheshasdroppedfrom16milliontomillionsincehydro-

4、electricplantswerebuiltontheColumbiaRiver.Damsallovertheworldhavehurtsomespecies.　　ThehighestdamintheUnitesStatesislocatednearOroville,California.TheOrovilleDamtowers230metersandismorethanamilewide.Thisdamwasbuiltin1968,22yearsaftertheHooverDam.TheHooverDam,ontheNevada-Arizonabordercontrol

5、stheColoradoriver.Itis221metershighandhasmillionhectare-metersofwater.　　ThehighestdamintheworldistheNurekDamontheVakhshRiverinTadzikistan,acountryincentralAsia.Thisdamis300meterstall.　　4.WhichofthefollowingstatementsisNOTtrueaccordingtothepassage?　　A.Somedamsarebuiltforcontrollingariver’sw

6、aterflow.　　B.Hydro-electricpowerisusuallyproducedthroughadam.　　C.Damscanofferenergyandtheyareharmlesstotheenvironment.　　D.Generallyspeaking,wherethereisadam,thereisaman-madelake.　　5.Thethirdparagraphmainlytellsus_____.　　A.howhydro-electricpowerisproducedB.Whataturbineisandhowitworks　　C.how

7、themagnetsandthemetalcoilswork　　D.howthefallingwaterpassesthroughaturbine　　damwhichcontrolstheColoradoriveris____.　　A.theOrovilleDamB.theHooverDamC.theNurekDamD.theVakhshDam　　CAB