大學英語六級閱讀模擬練習題和答案詳解

　　下面是小編整理的，希望對大家有幫助。

　　How Ozone Pollution Works

　　A*** The weather report on the radio or TV tells you that it is going to be sunny and hot and that an orange ozone alert has been issued. What is ozone? What does an orange alert mean? Why should you be concerned about it? In this article, we will examine what ozone is, how it is produced, what health hazards it poses and what you can do to reduce ozone pollution.

　　B*** Ozone is a molecule of three oxygen atoms bound together ***O3***. It is unstable and highly reactive. Ozone is used as a bleach, a deodorizing agent, and a sterilization agent for air and drinking water. At low concentrations, it is toxic. Ozone is found naturally in small concentrations in the stratosphere, a layer of Earth’s upper atmosphere. In this upper atmosphere, ozone is made when ultraviolet light from the sun splits an oxygen molecule ***O2***, forming two single oxygen atoms. If a freed atom collides with an oxygen molecule, it becomes ozone. Stratospheric ozone has been called “good” ozone because it protects the Earth’s surface from dangerous ultraviolet light.

　　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

　　文章主要介紹了什麼是臭氧，臭氧汙染的形成、危害，以及臭氧有利的一面。文章還具體介紹瞭如何自己手工製作檢測儀;如何避免暴露在臭氧之下;如何預防和減少臭氧汙染等。

　　答案解析

　　1. B 本題答案的資訊來自B段的倒數第二、三句話。原文中提到太陽紫外線將氧分子分成了兩個單獨的氧原子，氧原子與氧分子再結合就生成了臭氧。題幹正好表達了這個意思。ultraviolet rays即是原文中的ultraviolet light。

　　2. E 本題答案的資訊來自E段第一句話。題目中的find out about意為“弄清有關的情況”，和原文中的detect and monitor含義相對應;題目中的inyour own locale和原文中的in your own backyard相對應。

　　3. F 本題答案的資訊來自F段。F段提到人吸入臭氧後，它可以貫穿你的呼吸系統。接著提到它可能損害細支氣管、肺部等呼吸系統的部位，故可知長期暴露在臭氧下有損呼吸系統。

　　4. N 本題答案的資訊來自N段第五句話，題幹是對本句的同義轉述。

　　5. C 本題答案的資訊來自C段的第二句話。原句中先說“果”後說“因”，題目將

　　“因”提前，然後說“果”;原文中的man-made與題幹中的artificial相對應; 原文中的termed與題幹中的known as相對應。

　　6. M 本題答案的資訊來自M段第二句和最後一句話。原文中第二句話首先提到

　　Ozone is “good” when it is in the stratosphere.，在最後一句中提到臭氧為什麼有益;原文中的beneficial與題幹中的helpfUl相對應;題目中的separates from對應原文中的prevents from。

　　7. J 本題答案的資訊來自J段第一、二、三句話。原文中J段的首句提到有幾種可以降低臭氧汙染的方法，接下來提到的一種方法是Do not use gasoline- powered lawn equipment during these times.由此推測Using gasoline-powered lawn equipment會導致臭氧汙染增加;而由第二句話可推測出原文中的 during these times指的是in the late spring, summer and early fall。

　　8. D 本題答案的資訊來自D段第一句話。原文提到臭氧汙染主要在城市和城市郊區出現，但因為風和汽車、卡車運輸的作用，農村也會發生臭氧汙染，題幹是對此的歸納。

　　9. K 本題答案的資訊來自K段第一句話。原文中的initiated和題目中的set up屬於同義轉換;原文中的stringent替換為了rigorous;原文中的reduce ozone pollution替換為了decrease ozone pollution。

　　10. H本題答案的資訊來自H段第一句話。題目中的keep you away from對應原文的protect yourself from;題目中的Pay close attention to 對應原文的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***震動***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***築造學***.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 ***潤滑的***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 ***岩漿*** 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，瞭解地震對減少其帶來的損失有著重要意義。本文講解了引發地震的因素、與地震有關的地殼板塊運動和地震的危害，並指出儘管人類還無法準確預測地震，但一些必要的防禦措施能夠減少地震帶來的損失。

　　答案解析

　　1. E 本題是對E段最後一句話的同義轉述。定位關鍵詞是Earthquake-related fatalities。原文用it’s not...that claims lives; it’s...結構指出“通常不是地殼晃動引起的死亡，而是伴隨而來的房屋倒塌或其他自然災害導致的死亡”，題目用...be caused by...not by...結構表達了同樣的意思。

　　2. C 本題是對C段最後兩句的歸納，題目將兩句話的含義概括為一句話。定位關鍵詞是 movements of the earth$s plates, volcanic eruptions, meteor impacts。

　　3. D 本題是對D段的總結。定位關鍵詞是get our attention。D段首句就提到每天都會發生地震，最後一句提到只有大地震才能引起人們的注意，本題就是對這兩句話的概括。

　　4. A 本題是對A段最後兩句的同義轉述。定位關鍵詞是shatter。題目中的the ground beneath their feet同義轉述了原文中的the ground we stand on。

　　5. N 本題是對N段最後兩句的概括。定位關鍵詞是better ways。文章最後一句提到，我們能做的就是增加我們對地震的認識，尋找更好的方法來應對它，與題幹表達一致。

　　6. K 本題是對K段第三句的同義轉述。定位關鍵詞是hardly predictable。原文提到：雖然我們對地震有了更深的瞭解，但地震仍然不受我們的控制，地震是無法預測的，人們不可能得知地震什麼時候會發生，表達與題幹一致。

　　7. B 本題是對B段第三、四句的同義轉述。定位關鍵詞是cause earthquakes。題目中的found out同義轉述了原文中的identified。

　　8. L 本題是對L段最後兩句的概括。定位關鍵詞是designed。原文提到：過去50年我們在應對地震方面取得了進步，尤其是在建築工程領域。我們用特殊材料加固房屋以應對地震的破壞，我們設計足夠靈活的房屋，確保地震不會導致房屋倒塌，這與題幹表達的完全一致。

　　9. F 本題是F段中舉例的一部分。定位關鍵詞是the theory of plate tectonics。原文提到科學家用the idea of plate tectonics解釋很多現象，其中之一就是the apparent movement of continents over time。

　　10. I 本題是對I段最後一句的同義轉述。定位關鍵詞是convergent plate boundaries。題幹中的refer to與原文中的are called屬於同義轉述。