Howcanwegetridofgarbage?Dowehaveenoughenergysourcestomeetourfutureenergyneeds?
Thesearetwoimportantquestionsthatmanypeopleareaskingtoday.Somepeoplethinkthatmenmightbeabletosolvebothproblemsatthesametime.Theysuggestusinggarbageasanenergysource.
Foralongtimepeopleburiedgarbageordumpeditonemptyland.Nowemptylandisscarce.Butmoreandmoregarbageisproducedeachyear.Butgarbagecanbeagoodfueltouse.Thethingsingarbagedonotlooklikecoalpetroleumornaturalgas;buttheyarechemicallysimilartothesefossilfuels.Asweuseupourfossil-fuelsupplieswemightbeabletousegarbageasanenergysource.
Burninggarbageisnotanewidea.SomecitiesinEuropeandtheUnitedStateshavebeenburninggarbageforyears.Theheatthatisproducedbyburninggarbageisusedtoboilwater.Thesteamthatisproducedisusedtomakeelectricityortoheatnearbybuildings.InParisFrancesomepowerplantsburnalmost2millionmetrictonsofthecity'sgarbageeachyear.Theamountofenergyproducedisaboutthesameastheworldproducedbyburningalmostahalfmillionbarrelsofoil!
Butthereareproblemsinusinggarbageasafuel.Garbagethatburnseasilysuchasfoodscrapsandpapermustbeseparatedfrommetalsglassandothermaterialsthatdonotburneasily.Thisseparationprocessisnormallycostly.Anotherproblemisthatburninggarbagecanpollutetheair.
Ourfossilfuelsuppliesarelimited.Burninggarbagemightbeonekindofenergysourcethatwecanusetohelpmeetourenergyneeds.Thismethodcouldalsoreducetheamountofgarbagepilingupontheearth.
53.Whattwoproblemscanbesolvedbyburninggarbage?
A.Theshortageofenergy;Airpollution.
B.Theshortageofenergy;theshortageofemptylandforholdinggarbage.
C.Airpollution;theshortageofemptylandforholdinggarbage.
D.Airpollution;theshortageoffossilfuel.
54.WhichofthefollowingisNOTaresultofburninggarbage?
A.Theheatproducedisusedtoboilwater.
B.Thesteamproducedisusedtomakeelectricity.
C.Thegarbageburnedisturnedintofossilfuels.
D.Thesteamproducedisusedtoheatbuildings.
55.Accordin