2018年6月大学英语四级听力真题第二套:2018年6月大学英语四级听力美文第:HotterorColder?

【#四六级考试# 导语】英语听力是英语四级考试中的重要组成部分，对于中国的考生，日常英文听说机会少，缺少听力训练，所以在备考大学英语四级时，需要加强对四级听力的训练。针对这一情况，®文档大全网英语四级频道总结为大家整理了《2018年6月大学英语四级听力美文第:Hotter or Colder ?》一文，希望对大家备考有所帮助，并预祝同学们高分通过考试。

　英语四级听力美文:Hotter or Colder ?

　　It was once thought that air pollution affected only the area immediately around large citieswith factories and/or heavy automobile traffic.

　　Today, we know that although these are the areas with the worst air pollution, the problem isliterally worldwide.

　　On several occasions over the past decade, a heavy cloud of air pollution has covered theentire eastern half of the United States and led to health warnings even in rural areas awayfrom any major concentration of manufacturing and automobile traffic.

　　In fact, the climate of the entire earth may be affected by air pollution.

　　Some scientists feel that the increasing concentration of carbon dioxide in the air resultingfrom the burning of fossil fuels (coal and oil) is creating a “greenhouse effect” — holding inheat reflected from the earth and raising the world's average temperature.

　　If this view is correct and the world's temperature is raised only a few degrees, much of thepolar ice cap will melt and cities such as New York, Boston, Miami, and New Orleans will beunder water.

　　Another view, less widely held, is that increasing particulate matter in the atmosphere isblocking sunlight and lowering the earth's temperature — a result that would be equallydisastrous.

　　A drop of just a few degrees could create something close to new ice age and would makeagriculture difficult or impossible in many of our top farming areas.

　　At present we do not know for sure that either of these conditions will happen (though onerecent government report prepared by experts in the field concluded that the greenhouseeffect is very likely).

　　Perhaps, if we are very lucky, the two tendencies will offset each other and the world'stemperature will stay about the same as it is now.

2018年6月大学英语四级听力美文第:Hotter or Colder ?.doc

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