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ID:42927158
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页数:31页
时间:2019-09-23
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1、EnvironmentaIProbIems环境问题ThedeveIopmentofscienceandtechnologyinthetwentiethcenturyhasgreatIyraisedthequaIityofhumanIifebutatthesametimeithasaIsoIedtosomeseriousprobIemsthreateningthesurvivaIofhumanbeings.Amongtheseareissuesconcerningenvironmentaiprotection.Doyouknowwhatthegreenh
2、ouseeffectis?WhatisacidrainortheozonehoIe?ThefollowingpassagediscussessomeoftheenvironmentaIprobIemsandthewaystosoIvethem.20世纪的科技发展大大提高了人类的生活质量,但同时也引发了一些严重的问题,威胁着人类的生存。其中有些问题与环境保护有关。你知道什么是温室效应吗?什么是酸雨?什么是黑洞?下面这篇文章讨论了一些环境问题及其解决办法。Beforehumanscameonthescene,theworIdchangedonIyslowl
3、y.ThecIimatewarmedandcooIedfnewpIantsandanimaIsevolvedandbecameextinetintheirturn,andseaIeveIsroseandfeIIoverperiodsofthousands,ifnotmiIIions,ofyears・ButduringtheIasttwothousandyearstherehavebeenverygreatchanges・Forestshavedisappeared,rivercourseshavebeenchanged.andlargeareasofn
4、aturaIvegetationhaveturnedintofarmlandandcities.ThereareseriousproblemsforthesurvivaIofthehumanrace.人类出现以前,世界变化非常缓慢。气候变暖又转冷,新的植物、动物进化又渐次灭亡,海平面上升而后下降,这样的变化如果不是需要数百万年的时间,也是需要数千年的时间的。然而,在过去的两千年间,世界的变化非常显著。森林消失,河流改道,大片大片草木自然生长的地方变成了农场和城市。人类的生存面临着严峻的问题。ThegreenhouseeffectItmaybecoldo
5、utside,butonasunnydayitcanbehotinagreenhouse・SomeofthegasesintheEarth'satmosphereactliketheglassinagreenhouse.RadiantheatfromtheSuncanpassthroughthemtowarmtheEarthbeIow・ButthegroundaIsoIosesheatbyradiation.The"greenhousegases"sendsomeofthisheatbacktowardstheEarth,ssurfaceandheIp
6、tokeepitwarm・However,byburningfueIsandforests,weareputtingIargerandIargeramountsofthesegreenhousegasesintotheatmosphere.AsaresuIt.theEarthisslowlywarmingup.Thisiscalledthegreenhouseeffect・温室效应温室外面也许很冷,但晴天时室内就会很热。地球大气层中的一些气体起着类似温室玻璃的作用。太阳辐射热可以穿过这些气体使地球变暖。不过地面也会通过辐射散发热量。“温室气体”把热量辐
7、射回地球表面,使之保温。然而,由于不断地燃烧燃料、烧毁森林,我们正在把越来越多的温室气体释放到大气层。结果,地球在逐渐变暖。这就是温室效应。GreenhousegasesCarbondioxideisthemaingreenhousegasintheatmosphere.Animals(likeourseIves)giveoutcarbondioxidewhentheybreathe,whiIepIantsbreatheincarbondioxide・Inthisway,animalsandpIantskeeptheatmosphereinbaIanc
8、eandtheamountofcarbondioxidestaysthesame・Howeve
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