CET4

Passage One

Questions 56 t0 60 are based on the following passage.

It was once thought that air pollution affected only the area immediately around large cities with factories and heavy automobile traffic.Today, we know 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 entire eastern half of the United States and led to health warnings even in rural areas away from any major concentration of manufacturing and automobile traffic.In fact， the very climate of the entire earth may be affected by air pollution.

Some scientists feel 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”-holding in 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 Y0rk，Boston，Miami，and New Orleans will be under water.

Another view, less widely held，is that increasing particulate 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 new ice age and would make agriculture 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 one recent government report prepared by experts in the field concluded that the greenhouse effect is very likely.Perhaps，if we are very lucky, the two tendencies will offset each other and the world’s temperature will stay about the same as it is now.

56.According to the passage，people today think that air pollution________.

A)exists merely in urban and industrial areas

B)may have an effect on the entire earth

C)causes widespread damage in the countryside

D)is not so serious as it used to be

57.The“greenhouse effect” results from________.

A)the concentration of carbon dioxide in the air

B)the increasing particulate matter in the atmosphere

C)the burning of firewood

D)the blocking of sunlight

58.What does the author think of the possibility of a new ice age?

A)He rejects it as being ungrounded.

B)He holds the same view.

C)He is uncertain of its occurrence.

D)He thinks that would happen soon.

59.The word“offset”(Line 3，Para.4)means________.

A)slip into

B)catch up with

C)set up

D)make up for

60.The passage is mainly about__________.

A)the potential effect of air pollution

B)the possibility of a new ice age

C)the effects of global warming

D)the causes of climate change

56. 【解析】 B。细节题。第一段第二句提到，“现今，虽然我们已经知道这些地方的空气污染最为严重，但是空气污染实际上是全球性的问题。”故答案为B。

57. 【解析】A。细节题。第二段第一句指出，科学家认为，煤和油的燃烧会不断增加空气中的二氧化碳含量，由此导致温室效应。故答案为A。

58. 【解析】 C。态度题。最后一段中作者指出，目前我们并不确定这两种情况是否会发生……。这两种情况指的就是上文所述：温室效应和冰河世纪再次降临的可能性。故答案为C。

59. 【解析】 D。语义题。此句意思是：但如果我们非常幸运，这两种趋势或许会相互offset，地球气温会像现在一样，保持不变。由此可知，“offset”在文中的意思应为“弥补，抵消”。故答案为D。

60. 【解析】A。主旨题。综观全文，文章主要讲述了空气污染可能造成的严重后果。选项B、C均只概括了文章的部分内容，D项文章未提到。故答案为A。

编辑推荐：2014年英语四级考试阅读理解练习及答案

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