大学英语六级阅读模拟练习题和答案详解

　　C) Ozone can also be found in the troposphere, the lowest layer of the atmosphere. Tropospheric ozone (often termed “ bad ” ozone) is man - made, a result of air pollution from internal combustion engines and power plants. Automobile exhaust and industrial emissions release a family of nitrogen oxide gases (NOx) and volatile organic compounds (VOC), by-products of burning gasoline and coal. NOx and VOC combine chemically with oxygen to form ozone during sunny, high- temperature conditions of late spring, summer and early fall. High levels of ozone are usually formed in the heat of the afternoon and early evening, dissipating during the cooler nights.

　　D) Although ozone pollution is formed mainly in urban and suburban areas, it ends up in rural areas as well, carried by prevailing winds or resulting from cars and trucks that travel into rural areas. Significant levels of ozone pollution can be detected in rural areas as far as 250 miles downwind from urban industrial zones.

　　E) You can make ozone test strips to detect and monitor ozone levels in your own backyard or around your school. You will need corn starch, filter paper (coffee filters work well) and potassium iodide (can be ordered from a science education supplier such as Carolina Biological Supply or Fisher Scientific). Basically, you make a paste from water, corn starch and potassium-iodide, and you paint this paste on strips of filter paper. You then expose the strips to the air for eight hours. Ozone in the air will react with the potassium iodide to change the color of the strip. You will also need to know the relative humidity, which you can get from a newspaper, weather broadcast or home weather station.

　　F) When you inhale ozone, it travels throughout your respiratory tract. Because ozone is very corrosive, it damages the bronchioles and alveoli in your lungs, air sacs that are important for gas exchange. Repeated exposure to ozone can inflame lung tissues and cause respiratory infections.

　　G) Ozone exposure can aggravate existing respiratory conditions such as asthma, reduce your lung function and capacity for exercise and cause chest pains and coughing. Young children, adults who are active outdoors and people with respiratory diseases are most susceptible to the high levels of ozone encountered during the summer. In addition to effects on humans, the corrosive nature of ozone can damage plants and trees. High levels of ozone can destroy agricultural crops and forest vegetation.

　　H) To protect yourself from ozone exposure, you should be aware of the Air Quality Index (AQI) in your area every day—you can usually find it in the newspaper or on a morning weather forecast on TV or radio. You should also be familiar with the U.S. Environmental Protection Agency (EPA) guide for ozone-alert values.

　　I) What do the numbers in the AQI mean? The AQI measures concentrations of five air pollutants: ozone, sulfur dioxide, particulate matter, carbon monoxide and nitrogen dioxide. The EPA has chosen these pollutants as criteria pollutants, but these are not all of the pollutants in the air. These concentrations are compared to a standard set out in federal law. An index value of 100 means that all of the criteria pollutants are at the maximum level that is considered safe for the majority of the population. To reduce your exposure to ozone, you should avoid exercising during afternoon and early evening hours in the summer.

　　J) There are several ways you can help to decrease ozone pollution. Limit using your automobile during afternoon and early evening hours in the late spring, summer and early fall. Do not use gasoline-powered lawn equipment during these times. Do not fuel your car during these times. Do not light fires or outdoor grills during these times. Keep the engine of your car or boat tuned. Make sure that your tires are properly inflated. Use environmentally safe paints, cleaning and office products (some of these chemicals are sources of VOC).

　　K) Besides personal attempts to reduce ozone pollution, the EPA has initiated more stringent air-quality standards (such as the Clean Air Act and its modifications) to reduce air pollution. Compliance with these standards by industries, manufacturers and state and local governments has significantly reduced the levels of many common air pollutants.

　　L) With continued conservation and reduction practices, adherence to ozone-pollution warnings, research and government regulation, ozone-pollution levels should

　　continue to fall. Perhaps future generations will not be threatened by this environmental pollutant.

　　M) The thing that determines whether ozone is good or bad is its location. Ozone is ‘‘good，，when it is in the stratosphere. The stratosphere is a layer of the atmosphere starting at the level of about 6 miles (about 10 kilometers) above sea level. The stratosphere naturally contains about six parts per million of ozone, and this ozone is very beneficial because it absorbs UV radiation and prevents it from reaching us.

　　N) Ozone is “bad” when it is at ground level. Ozone is a very reactive gas that is hard on lung tissue. It also damages plants and buildings. Any ozone at ground level is a problem. Unfortunately, chemicals in car exhaust and chemicals produced by some industries react with light to produce lots of ozone at ground level. In cities, the ozone level can rise to a point where it becomes hazardous to our health. That’s when you hear about an ozone warning on the news.

　　1. When ultraviolet rays from the sun separate an oxygen molecule into two single oxygen atoms in the stratosphere, the combination of a single oxygen atom and an oxygen molecule forms ozone.

　　2. You can make ozone test strips by yourself to find out about ozone levels in your own locale.

　　3. Long-time exposure to ozone is badly harmful to our respiratory system.

　　4. Chemicals in industrial waste gas and vehicle exhaust react with light to form lots of ozone at ground level.

　　5. Internal combustion engines and power plants cause the artificial tropospheric ozone, also known as “bad” ozone.

　　6. Ozone is very helpful because it absorbs UV radiation and separates us from it.

　　7. Using gasoline-powered lawn equipment in the late spring, summer and early fall may increase ozone pollution.

　　8. Ozone pollution occurs in urban and suburban areas as well as in rural areas.

　　9. In order to decrease ozone pollution, the EPA has set up more rigorous air-quality standards.

　　10. Pay close attention to the Air Quality Index in your area every day can keep you away from ozone exposure.

　　文章精要

　　文章主要介绍了什么是臭氧，臭氧污染的形成、危害，以及臭氧有利的一 面。文章还具体介绍了如何自己手工制作检测仪;如何避免暴露在臭氧之下;如 何预防和减少臭氧污染等。

　　答案解析

　　1. B 本题答案的信息来自B段的倒数第二、三句话。原文中提到太阳紫外线将 氧分子分成了两个单独的氧原子，氧原子与氧分子再结合就生成了臭氧。 题干正好表达了这个意思。ultraviolet rays即是原文中的ultraviolet light。

　　2. E 本题答案的信息来自E段第一句话。题目中的find out about意为“弄清有关 的情况”，和原文中的detect and monitor含义相对应;题目中的inyour own locale和原文中的in your own backyard相对应。

　　3. F 本题答案的信息来自F段。F段提到人吸入臭氧后，它可以贯穿你的呼吸系统。接着提到它可能损害细支气管、肺部等呼吸系统的部位，故可知长期 暴露在臭氧下有损呼吸系统。

　　4. N 本题答案的信息来自N段第五句话，题干是对本句的同义转述。

　　5. C 本题答案的信息来自C段的第二句话。原句中先说“果”后说“因”，题目将

　　“因”提前，然后说“果”;原文中的man-made与题干中的artificial相对应; 原文中的termed与题干中的known as相对应。

　　6. M 本题答案的信息来自M段第二句和最后一句话。原文中第二句话首先提到

　　Ozone is “good” when it is in the stratosphere.，在最后一句中提到臭氧为什 么有益;原文中的beneficial与题干中的helpfUl相对应;题目中的separates from对应原文中的prevents from。

　　7. J 本题答案的信息来自J段第一、二、三句话。原文中J段的首句提到有几种可以降低臭氧污染的方法，接下来提到的一种方法是Do not use gasoline- powered lawn equipment during these times.由此推测Using gasoline-powered lawn equipment会导致臭氧污染增加;而由第二句话可推测出原文中的 during these times指的是in the late spring, summer and early fall。

　　8. D 本题答案的信息来自D段第一句话。原文提到臭氧污染主要在城市和城市郊区出现，但因为风和汽车、卡车运输的作用，农村也会发生臭氧污染， 题干是对此的归纳。

　　9. K 本题答案的信息来自K段第一句话。原文中的initiated和题目中的set up属于同义转换;原文中的stringent替换为了rigorous;原文中的reduce ozone pollution替换为了decrease ozone pollution。

　　10. H本题答案的信息来自H段第一句话。题目中的keep you away from对应原文的protect yourself from;题目中的Pay close attention to 对应原文的should be aware of。

　　Earthquakes

　　A) An earthquake is one of the most terrifying phenomena that nature can dish up. We generally think of the ground we stand on as “rock-solid” and completely stable. An earthquake can shatter (粉碎)that perception instantly, and often with extreme violence.

　　B) Up until relatively recently, scientists only had unproven guesses as to what actually caused earthquakes. Even today there is still a certain amount of mystery surrounding them, but scientists have a much clearer understanding. There has been enormous progress in the past century. Scientists have identified the forces that cause earthquakes, and developed technology that can tell us an earthquake"s magnitude and origin. The next hurdle is to find a way of predicting earthquakes, so they don’t catch people by surprise. In this article, we’ll find out what causes earthquakes, and we’ll also find out why they can have such a devastating effect on us.

　　C) An earthquake is a vibration(震动)that travels through the earth’s crust. Technically, a large truck that rumbles down the street is causing a mini-earthquake, if you feel your house shaking as it goes by; but we tend to think of earthquakes as events that affect a fairly large area, such as an entire city. All kinds of things can cause earthquakes: volcanic eruptions, meteor(流星)impacts, underground explosions (an underground nuclear test, for example), collapsing structures (such as a collapsing mine). But the majority of naturally-occurring earthquakes are caused by movements of the earth’s plates.

　　D) We only hear about earthquakes in the news every once in a while, but they are actually an everyday occurrence on our planet. According to the United States Geological Survey, more than 3 million earthquakes occur every year. That’s about 8,000 a day, or one every 11 seconds! The vast majority of these 3 million quakes are extremely weak. The law of probability also causes a good number of stronger quakes to happen in uninhabited places where no one feels them. It is the big

　　quakes that occur in highly populated areas that get our attention.

　　E) Earthquakes have caused a great deal of property damage over the years, and they have claimed many lives. In the last hundred years alone, there have been more than 1.5 million earthquake-related fatalities. Usually, it’s not the shaking ground itself that claims lives; it’s the associated destruction of man-made structures and other natural disasters it causes, such as tsunamis, avalanches (雪崩)and landslides.

　　F) The biggest scientific breakthrough in the history of seismology—the study of earthquakes—came in the middle of the 20th century, with the development of the theory of plate tectonics(筑造学).Scientists proposed the idea of plate tectonics to explain a number of peculiar phenomena on earth, such as the apparent movement of continents over time, the clustering of volcanic activity in certain areas and the presence of huge ridges at the bottom of the ocean.

　　G) The basic theory is that the surface layer of the earth—the lithosphere—is comprised of many plates that slide over the lubricating (润滑的)asthenosphere layer. At the boundaries between these huge plates of soil and rock, three different things can happen.

　　H) Plates can move apart. If two plates are moving apart from each other, hot, molten rock flows up from the layers of mantle below the lithosphere. This magma (岩浆) comes out on the surface (mostly at the bottom of the ocean), where it is called lava (熔岩).As the lava cools, it hardens to form new lithosphere material, filling in the gap. This is called a divergent plate boundary.

　　I) Plates can push together. If the two plates are moving toward each other, one plate typically pushes under the other one. This plate below sinks into the lower mantle layers, where it melts. At some boundaries where two plates meet, neither plate is in a position to push under the other, so they both push against each other to form mountains. The lines where plates push toward each other are called convergent plate boundaries.

　　J) Plates slide against each other. At other boundaries, plates simply slide by each other—one moves north and one moves south, for example. While the plates don’t drift directly into each other at these transform boundaries, they are pushed tightly together. A great deal of tension builds at the boundary.

　　K) We understand earthquakes a lot better than we did even 50 years ago, but we still can’t do much about them. They are caused by fundamental, powerful geological processes that are far beyond our control. These processes are also fairly unpredictable, so it’s not possible at this time to tell people exactly when an earthquake is going to occur. The first detected earthquake waves will tell us that more powerful vibrations are on their way, but this only gives us a few minutes’ warning, at most.

　　L) So what can we do about earthquakes? The major advances over the past 50 years have been in preparedness, particularly in the field of construction engineering. In 1973, the Uniform Building Code, an international set of standards for building construction,7 added7 specifications7 to7 strengthen7 buildings7 against7 the7 force7 of7 earthquake7 waves.7 This7 includes7 strengthening7 support7 material7 as7 well7 as7 designing buildings so they are flexible enough to absorb vibrations without falling or deteriorating. It’s very important to design structures that can undergo this sort of attack, particularly in earthquake -prone areas.

　　M) Another component of preparedness is educating the public. The United States Geological Survey (USGS) and other government agencies have produced several brochures explaining the processes involved in an earthquake and giving instructions on how to prepare your house for a possible earthquake, as well as what to do when a quake hits.

　　N) In the future, improvements in prediction and preparedness should further minimize the loss of life and property associated with earthquakes. But it will be a long time, if ever, before we’ll be ready for every substantial earthquake that might occur. Just like severe weather and disease, earthquakes are an unavoidable force generated by the powerful natural processes that shape our planet. All we can do is increase our understanding of the phenomenon and develop better ways to deal with it.

　　1. Earthquake-related fatalities are usually caused by buildings，collapse and other ensuing natural disasters, not by the shaking ground itself.

　　2. Besides movements of the earth’s plates, other forces such as volcanic eruptions, meteor impacts and so on, can also cause earthquakes.

　　3. Earthquakes actually occur every day; most of them are not big enough to get our attention.

　　4. People generally think the ground beneath their feet is completely stable, but earthquakes shatter that idea in no time.

　　5. We cannot prevent earthquakes but we can actively find better ways to face them.

　　6. Earthquakes are hardly predictable, and people cannot be told when an earthquake is going to occur.

　　7. Scientists have found out forces that cause earthquakes through years of efforts.

　　8. Architects now have designed flexible buildings to minimize the damages of earthquakes.

　　9. Scientists use the theory of plate tectonics to explain the apparent movement of continents over time.

　　10. The convergent plate boundaries refer to the lines where plates push toward each other.

　　文章精要

　　地震危害巨大，了解地震对减少其带来的损失有着重要意义。本文讲解了引 发地震的因素、与地震有关的地壳板块运动和地震的危害，并指出尽管人类还无 法准确预测地震，但一些必要的防御措施能够减少地震带来的损失。

　　答案解析

　　1. E 本题是对E段最后一句话的同义转述。定位关键词是Earthquake-related fatalities。原文用it’s not...that claims lives; it’s...结构指出“通常不是地壳晃 动引起的死亡，而是伴随而来的房屋倒塌或其他自然灾害导致的死亡”， 题目用...be caused by...not by...结构表达了同样的意思。

　　2. C 本题是对C段最后两句的归纳，题目将两句话的含义概括为一句话。定位关键词是 movements of the earth$s plates, volcanic eruptions, meteor impacts。

　　3. D 本题是对D段的总结。定位关键词是get our attention。D段首句就提到每天都会发生地震，最后一句提到只有大地震才能引起人们的注意，本题就是 对这两句话的概括。

　　4. A 本题是对A段最后两句的同义转述。定位关键词是shatter。题目中的the ground beneath their feet同义转述了原文中的the ground we stand on。

　　5. N 本题是对N段最后两句的概括。定位关键词是better ways。文章最后一句提到，我们能做的就是增加我们对地震的认识，寻找更好的方法来应对它， 与题干表达一致。

　　6. K 本题是对K段第三句的同义转述。定位关键词是hardly predictable。原文提到：虽然我们对地震有了更深的了解，但地震仍然不受我们的控制，地震 是无法预测的，人们不可能得知地震什么时候会发生，表达与题干一致。

　　7. B 本题是对B段第三、四句的同义转述。定位关键词是cause earthquakes。题目中的found out同义转述了原文中的identified。

　　8. L 本题是对L段最后两句的概括。定位关键词是designed。原文提到：过去50年我们在应对地震方面取得了进步，尤其是在建筑工程领域。我们用特殊 材料加固房屋以应对地震的破坏，我们设计足够灵活的房屋，确保地震不 会导致房屋倒塌，这与题干表达的完全一致。

　　9. F 本题是F段中举例的一部分。定位关键词是the theory of plate tectonics。原文提到科学家用the idea of plate tectonics解释很多现象，其中之一就是the apparent movement of continents over time。

　　10. I 本题是对I段最后一句的同义转述。定位关键词是convergent plate boundaries。题干中的refer to与原文中的are called属于同义转述。