There was one thought that air pollution affected only the area immediately around large cities with factories and heavy automob

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问题    There was one thought that air pollution affected only the area immediately around large cities with factories and heavy automobile traffic. At present, we realize that although these are the areas with the worst air pollution, the problem is literally worldwide. On several occasions over the past decade, a heavy cloud of air pollution has covered the east of the United States and brought health warnings in rural areas away from any major concentration of manufacturing and automobile traffic. In fact, the very climate of the entire earth may be infected by air pollution. Some scientists consider that the increasing concentration of carbon dioxide in the air resulting from the burning of fossil fuels (coal and oil) is creating a " greenhouse effect" —conserving heat 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 the polar ice cap will melt and cities such as New York, Boston, Miami, and New Orleans will be in water.
   Another view, less widely held, is that increasing particular matter in the atmosphere is blocking sunlight and lowering the earth’ s temperature-—a result that would be equally disastrous. A drop of just a few degrees could create something close to a new ice age, and would make agriculture difficult or impossible in many of our top farming areas. Today we do not know for sure that either of these conditions will happen (though one recent government report drafted by experts in the field concluded that the greenhouse effect is very possible). Perhaps, if we are lucky enough, the two tendencies will offset each other and the world’ s temperature will stay about the same as it is now.
The word "offset" in the second paragraph could be replaced by______.

选项 A、slip into
B、make up for
C、set up
D、catch up with

答案B

解析 推理题。文章提到了两种趋势,即地球温度上升和地球温度下降。offset所在句意为“如果我们足够幸运,也许这两种趋势将相互offset,全球温度不变”。由“全球温度不变”可知,这两种趋势只有相互抵消,才能保持气温不变,故offset在这里是“抵消”的意思。选项A(进入,滑入)、选项C(建立,设立)、选项D(赶上,追赶)均没有“相互抵消”的意思。选项B(弥补,补充)与“抵消”意思相近,故本题选B。
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