大学英语六级综合-阅读(三)及答案解析.doc

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1、大学英语六级综合-阅读(三)及答案解析(总分：50.00，做题时间：90 分钟)一、Passage One(总题数：1，分数：10.00)EarthquakesAn 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,

2、 and often with extreme violence.Up until relatively recently, scientists only had unsubstantiated (无确实证据的) 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

3、 progress in the past century: Scientists have identified the forces that cause earthquakes, and developed technology that can tell us an earthquakes magnitude and origin. The next hurdle is to find a way of predicting earthquakes, so they dont catch people by surprise.In this article, well find out

4、 what causes earthquakes, and well also find out why they can have such a devastating effect on us.Shaking GroundAn earthquake is a vibration (震动) that travels through the earths crust. Technically, a large truck that rumbles down the street is causing a mini-earthquake, if you feel your house shaki

5、ng 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 eruptionsmeteor impactsunderground explosions (an underground nuclear test, for example)collapsing structures (such as a collaps

6、ing mine)But the majority of naturally-occurring earthquakes are caused by movements of the earths plates.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 millio

7、n earthquakes occur every year. Thats 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 occu

8、r in highly populated areas that get our attention.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, its not the shaking ground itsel

9、f that claims lives; its the associated destruction of manmade structures and the instigation (发起) of other natural disasters, such as tsunamis, avalanches (雪崩) and landslides. Sliding PlatesThe biggest scientific breakthrough in the history of seismology-the study of earthquakes-came in the middle

10、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 pr

11、esence of huge ridges at the bottom of the ocean.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) athenosphere layer. At the boundaries between these huge plates of soil and rock, three different things can happ

12、en: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 li

13、thosphere material, filling in the gap. This is called a divergent plate boundary.Plates can push together. If the two plates are moving toward each other, one plate typically pushes under the other one. This sub-ducting plate sinks into the lower mantle layers, where it melts. At some boundaries wh

14、ere two plates meet, neither plate is in a position to sub-duct 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.Plates slide against each other. At other boundaries, plates simply slide by e

15、ach other-one moves north and one moves south, for example. While the plates dont drift directly into each other at these transform boundaries, they are pushed tightly together. A great deal of tension builds at the boundary.Dealing with EarthquakesWe understand earthquakes a lot better than we did

16、even 50 years ago, but we still cant 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 its not possible at this time to tell people exactly when an earthquake is going to occur. The fir

17、st detected seismic waves will tell us that more powerful vibrations are on their way, but this only gives us a few minutes warning, at most.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

18、. In 1973, the Uniform Building Code, an international set of standards for building construction, added specifications to fortify buildings against the force of seismic waves. This includes strengthening support material as well as designing buildings so they are flexible enough to absorb vibration

19、s without falling or deteriorating. Its very important to design structures that can take this sort of punch, particularly in earthquake-prone areas.Another component of preparedness is educating the public. The United States Geological Survey (USGS) and other government agencies have produced sever

20、al 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.In the future, improvements in prediction and preparedness should further minimize the loss of life and property ass

21、ociated with earthquakes. But it will be a long time, if ever, before well 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 increa

22、se our understanding of the phenomenon and develop better ways to deal with it.（分数：10.00）(1).Scientists had unsubstantiated guesses as to _ up until relatively recently.（分数：1.00）A.when actually earthquakes happenedB.what actually caused earthquakesC.how earthquakes happenedD.where actually earthquak

23、es happened(2).What is an earthquake?（分数：1.00）A.An earthquake is the most terrifying phenomena that nature can present to human beings.B.An earthquake can shatter our world instantly, and often with extreme violence.C.An earthquake is a vibration that travels through the earths core.D.An earthquake

24、is a vibration that travels through the earths crust.(3).The majority of naturally-occurring earthquakes are caused by _.（分数：1.00）A.volcanic eruptionsB.meteor impactsC.collapsing structuresD.movements of the earths plates(4).How many earthquakes occur every day according to the United States Geologi

25、cal Survey?（分数：1.00）A.More than 3 million.B.1.5 million.C.About 8,000.D.11.(5).Scientists proposed the idea of plate tectonics to explain_.（分数：1.00）A.a number of peculiar phenomena on earthB.a number of regular phenomena on earthC.the clustering of volcanic activity in uncertain areasD.the presence

26、of huge ridges at the top of the ocean(6).The surface layer of the earth is the lithosphere, which is comprised of many plates that slide over_.（分数：1.00）A.the presence of huge ridgesB.the lubricating athenosphere layerC.the new lithosphere materialD.the clustering of volcanic activity(7).What will h

27、appen if two plates are moving apart from each other?（分数：1.00）A.One plate typically pulls the other one.B.One plate typically pushes under the other one.C.The convergent plate boundaries will be formed.D.Hot, molten rock flows up from the layers of mantle below the lithospher(8).The convergent plate

28、 boundaries refer to the lines where plates_.（分数：1.00）填空项 1:_(9).The major advances over the past 50 years have been in preparedness, particularly in the field of construction engineering and_.（分数：1.00）填空项 1:_(10).In the future, improvements in prediction and preparedness should further minimize the

29、 loss of _ associated with earthquakes.（分数：1.00）填空项 1:_二、Passage Two(总题数：1，分数：10.00)How Ozone Pollution WorksIntroduction to How Ozone Pollution WorksThe 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? Wh

30、at 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.Ozone is a molecule of three oxygen atoms bound together (O3). It is unstable and highly r

31、eactive. 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 Earths upper atmosphere. In this upper atmosphere, ozone is made when ult

32、raviolet light from the sun splits an oxygen molecule (O2), forming two single oxygen atoms. If a freed atom collides with an oxogen molecule, it becomes ozone. Stratospheric ozone has been called “good“ ozone because it protects the Earths surface from dangerous ultraviolet light.Ozone can also be

33、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 volatil

34、e 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, dissi

35、pating during the cooler nights.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 a

36、s far as 250 miles ( 150 km) downwind from urban industrial zones.Make Your Own Ozone DetectorYou can make ozone test strips to detect and monitor ozone levels in your own backyard or around your school. You will need:cornstarchfilter paper (coffee filters work well)potassium iodide (can be ordered

37、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

38、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. Avoiding and Reducing OzoneWhen you inhale ozone, it travels throughout your respiratory tract. Because ozone i

39、s 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.Ozone exposure can aggravate existing respiratory conditions such as asthma, reduce your lung fun

40、ction 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 d

41、amage plants and trees. High levels of ozone can destroy agricultural crops and forest vegetation. Avoiding Ozone ExposureTo protect yourself from ozone exposure, you should be aware of the Air Quality Index (AQI) in your area everyday-you can usually find it in the newspaper or on a morning weather

42、 forecast on TV or radio. You should also be familiar with the U.S. Environmental Protection Agency (EPA) guide for ozone-alert values.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

43、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

44、 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.Reducing Ozone PollutionThere are several ways you can help to decrease ozone pollution:Limit using your automobile during afternoon and early

45、 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 infl

46、ated.Use environmentally safe paints, cleaning and office products (some of these chemicals are sources of VOC).Conserve energy.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

47、air pollution. Compliance with these standards by industries, manufacturers and state and local governments has significantly reduced the levels of many common air pollutants.With continued conservation and reduction practices, adherence to ozone- pollution warnings, research and government regulati

48、on, ozone-pollution levels should continue to fall. Perhaps future generations will not be threatened by this environmental pollutant.How can ozone be both good and bad?The thing that determines whether ozone is good or bad is its location.Ozone is “good“ when it is in the stratosphere. The stratosp

49、here 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.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. Unfo