阅读理解
AGreenhouseisabuildingmadeofglasswhichisusedforkeepingplantswarmwhentheoutsidetemperatureislow.Inasimilarwaythereareseveralgasesintheatmosphere(天气)whichtraptheheatproducedbythesunandpreventitfromescaping.Thesegasesareknownas“greenhousegases”andthewayinwhichtheytrapheatintheatmosphereiscalledthe“greenhouseeffect”.Thisisnotsimplyairpollution.Mostofthemaingreenhousegasesexistnaturallyinsmallamountsinouratmosphereandwithoutthemtheearthwouldbe30degreescolderandhumanlifewouldnotexist.Inotherwordsthegreenhouseeffectisanaturalcoursewhichistosomedegreehelpfultous.
Theproblemisthatinthelastcenturyandahalfwehavebeenputtingtoomanyofthesegasesintotheearth'satmospherebyburninglargequantitiesofcoalandoilandbycuttingdownforests.Therapidincreaseingreenhousegasesismakingtheworldwarmer.Theworld'stemperaturehasalreadygoneupbyhalfadegreethiscenturyandthesealevelhasrisenby10centimeters.Iftheamountofcarbondioxide(二氧化碳)intheatmospheredoublestherewillprobablybeariseintheearth'stemperatureofbetween1and4.Thismayseemasmallincreasebutitwouldbeenoughtocausemajorchangesingeographyandagriculture.Largeareasoftheworldwouldbefloodedandsomeareaswouldbecomedryandunabletoproducecrops.Itisimportanttootoconsiderthattheremaybeadelayofabout30yearsinthegreenhouseeffect.Thismeansthatweareprobablyexperiencingonlynowtheeffectofthegasesputintotheatmospherebeforethe1960s.Sincethenouruseofthesegaseshasgreatlyincreased.
1.“Greenhouseeffect”isactually________.
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A.thewayinwhichgasesareusedforkeepingplantswarm
B.anaturalcoursewhichistosomedegreehelpfultous
C.theway“greenhousegases”trapheatontheearth
D.thewholecourseinwhichgreenhousegasespreventheat
2.WhichofthefollowingstatementsisNOTtrue?
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A.Burningtoomuchcoalandoilproduceslotsofgreenhousegases.
B.Ithasbecomewarmerontheearthnowthaninthepast.
C.Gasesputintotheatmospherenowwilleffecttheearthyearslater.
D.Thetemperatureinagreenhouse