大学英语听力教程第三册听力原文(第二版-张民伦主编)

大学英语听力教程第三册（第二版）听力原文UNIT1 Is the Earth Being Squeezed DryPart1 Getting readySection B1. The Amazon forests are disappearing because of increased burning and tree removal. In September, satellite pictures showed more than 20000 fires burning in the Amazon. Experts say most of these fires were set by farmers. The farmers were attempting to clear land to grow crops. The World Wildlife Fund says another serious problem is that too many trees in the Amazon rain forest are being cut down. The World Wildlife Fund says the fires show the need for urgent international action to protect the world's rain forests. The group warns that without such action some forests could be lost forever.2. Environmental issues swell to the full in Berlin this week, for the UN sponsored conference on global warming and climate change is the first such meeting since the Rio summit three years ago. With scientists and governments now generally ready to accept that the earth climate is being affected by emissions of CO2 and other greenhouse gases, over a hundred countries are sending delegations. But how much progress has been made implementing the greenhouse gas reduction target agreed on at Rio? Simon Dary reports.Part2 The Earth at risk (1)I: Brian Cowles is the producer of a new series of documentaries called "The Earth at Risk" which can be seen on Channel 4 later this month. Each program deals with a different continent, doesn't it, Brian?B: That's right. We went to America, both North and South and then we went over to Africa and South-East Asia.I: And what did you find in each of these continents?B: Starting with Africa, our film shows the impact of the population on the environment. Generally speaking, this has caused the Sahara Desert to expand. It's a bit of a vicious circle we find. People cut down trees for firewood and their domestic animals eat all the available plants — and so consequently they have to move south as the Sahara Desert expands further south. I mean, soon the whole of Mali will become a desert. And in East Africa: here the grasslands are supporting too many animals and the result is, of course, there's no grass — nothing for the animals to eat.I: I see. And the next film deals with North America?B: That's right. In the USA, as you know, intensive agriculture requires a plentiful supply of rain for these crops to grow; I mean if there isn't enough rain the crops don't grow. And growing crops stabilize soil, without them the top soil just blows away. This is also true for any region that is intensely farmed — most of Europe, for example.I: And what did you find in South America?B: In South America (as in Central Africa and Southern Asia) tropical forests are being cut down at an alarming rate. This is done so that people can support themselves by growing food or to create ranches where cattle can be raised to be exported to Europe or America as tinned meat. The problem is that the soil is so poor that only a couple of harvests are possible before this very thin soil becomes exhausted. And it can't be fed with fertilizers like agricultural land in Europe. For example, in Brazil in 1982 an area of jungle the size of Britain and France combined was destroyed to make way for an iron ore mine. Huge numbers of trees are being cut down for exports as hardwood to Japan, Europe, USA to make things like luxury furniture. These forests can't be replaced — the forest soil is thin and unproductive and in just a few years, a jungle has become a waste land. Tropical forests contain rare plants (which we can use for medicines, for example) and animals — one animal or plant species becomes extinct every half hour. These forest trees also have worldwide effects. You know, they convert carbon dioxide into oxygen. The consequence of destroying forests is not only that the climate of that region changes (because there is less rainfall) but this change affects the whole world. I mean, over half the world's rain forest has been cut down this century.Part3 The Earth at risk (2)Section AI: So, Brian, would you agree that what we generally think of as natural disasters are in fact man-made?B: Yes, by and large. I mean, obviously not hurricanes or earthquakes, but take flooding, for example. Practically every year, the whole of Bangladesh is flooded and this is getting worse. You know, the cause is that forests have been cut down up in Nepal and India, I mean higher up-river in the Himalayas. Trees would hold rainfall in their roots, but if they've been cut down all the rain that falls in the monsoon season flows straight into the river Ganges and floods the whole country. The reason for flooding in Sudan is the same — the forests higher up the Blue Nile in Ethiopia have been destroyed too.I: Well, this all sounds terribly depressing. Um ... What is to be done? I mean, can anything be done, in fact?B: Yes, of course it can. First, the national governments have to be forward-looking and consider the results of their policies in ten or twenty years, not just think as far ahead as the next election. Somehow, all the countries in the world have to work together on an international basis. Secondly, the population has to be controlled in some way: there are too many people trying to live off too little land. Thirdly, we don't need tropical hardwood to make our furniture — it's a luxury people in the West must do without. Softwoods are just as good, less expensive and can be produced on environment-friendly "tree farms", where trees are replaced at the same rate that they are cut down.I: And, presumably, education is important as well. People must be educated to realize the consequences of their actions?B: Yes, of course.I: Well, thank you, Brian.Section BI: So, Brian, would you agree that what we generally think of as ... er... as er ... natural disasters are in fact man-made?B: Yes, by and large ... er ... I mean, obviously not hurricanes or earthquakes, but take flooding, for example. I mean, practically every year, the whole of Bangladesh is flooded and this is getting worse. You know, the cause is that forests have been cut down up in Nepal and India ... I mean ... higher up-river in the Himalayas. Trees ...er ... would hold rainfall in their roots, but if they've been cut down all the rain that falls in the monsoon season flows straight into the river Ganges and floods the whole country. The reason for flooding in Sudan is the same — the forests higher up the Blue Nile in Ethiopia have been destroyed too.Part4 The world is warming up.We know this because average temperatures are the highest since scientists started measuring them 600 years ago. The increase is about 0.2℃ every year. This may seem very slight, but we know that slight changes in temperature can have a big effect on other things. Most scientists now believe this global warming is due to human activity.Jeff Jenkins is head of Britain's Climate Prediction Center. He explains how global warming can happen."Sunlight strikes the earth and warms it up. At the same time heat leaves the earth, but part of that is trapped by carbon dioxide and other gases in the earth's atmosphere. That has been happening ever since the earth was formed. But the fear is that increasing amounts of carbon dioxide produced by industrial processes and transport and so on will lead to a greater warming of the earth's surface. So that's the global warming that people are concerned about."People are most concerned about the use of fossil fuels. Fossil fuels are oil, coal, wood and so on. When these burn, they produce the gas carbon dioxide. Many scientists agree that an increase in the amount of carbon dioxide and some of the gases in the atmosphere will increase the amount of warming. Computers are being used to predict what this may mean. They showed that there could be great changes in rainfall and the rise in the sea level as ice caps in the north and south poles melt. This could have a serious effect on agriculture according to Prof. Martin Perry of University College in London. He says it could become more difficult to grow food in the tropics at lower latitudes nearer to the equator."The most clear pattern emerging is the possibility of reduced potential production in lower latitude regions, and most generally speaking, increased potential in higher latitude regions. Lower latitude regions are already warm, to put itextremely simply, and plants there are quite near their limits of heat and drought stress. An increase in temperature or reduction in moisture would place limits on crop growth."Woman: Global warming could reduce food production in lower latitude regions. Lower latitude regions are already warm. Global warming could put more stress on plans and place limits on crop growth.Food production is only one area that could be affected. There could also be health and social problems. Prof. Antony MacMichael of the London School of Hygiene and Tropical Medicine believes that some rural areas are already suffering. And the insects and bacteria could spread disease more easily."Already a number of rural populations around the world are suffering from the decline of agricultural systems. Climate change would add to this. And we would expect that it would accelerate the flood of environmental refugees around the world. But it includes not just the food production systems, but the patterns of distribution of insects and infective agents around the world. It includes likely effects on patterns of hear-related food poisoning, water contamination and diarrhea diseases, lots of things like this that would respond sensitively to changes in climate."Woman: Global warming could affect the distribution of insects. Global warming could change patterns of heat-related food poisoning.Many countries now agree that something must be done to reduce the danger of global warming. But a worldwide agreement on lowering the production of carbon dioxide has been difficult to reach. This is because many economies depend on fossil fuels like oil. Scientists believe it's now the politicians in every region of the world who need to take action.Part5 Do you know…?Environment has taken rather a back seat politically since the Earth summit in Rio de Janeiro nearly 5 years ago. But the problems that meeting highlighted had not gone away. One environmental think tank — the International Food Policy Research Institute — has been looking at the future of water and its report reflects growing concern at the huge leap in usage over the past few years.In some parts of the world, water consumption has increased five fold. And the institute, known by its initials IFPRI, says shortages could soon become the trigger for conflict and a major barrier to feeding the world's growing population. Here's Richard Black of our Science Unit."It's often been said that water rather than oil will be the cause of warfare in the next century. According to the IFPRI report, the time when that happens might not be far away. The number of people affected by water shortage will increase ten fold over the next 30 years, it says, which could well lead to large scale conflicts.The main reason why water is becoming a scarce resource is agriculture, which now accounts for 70% of water consumption worldwide, 90% in some developing countries. Countless farmers have switched from growing indigenous crops for the home market to high yield export varieties, which inevitably need far more water. But the IFPRI report says that in some regions water shortage is now the single biggest impediment to feeding the population. Water scarcity also leads to water pollution. In the Indian State of West Bengal, for example, over extraction of water from bore holes has led to arsenic poisoning which is estimated to have affected two million people so far. But the IFPRI report calls for better water management worldwide including financial incentives to encourage conservation."------------------------------------------------------------------------------------------------------------------------Unit 2Part1 Getting readyA: Hello, I'm calling on behalf of the World Wildlife Fund.B: The what?A: The World Wildlife Fund. If you've got a few minutes I'd like to tell you what that means.B: Oh, all right.A: We work to conserve natural areas that contain endangered wildlife. The seas, for example, have become polluted by the industrialized world; whales are being hunted to extinction; turtles are rolled off their eggs when they come ashoreto breed or are slaughtered for their meat and oil …B: Oh.A: Crocodiles are killed to make handbags and shoes; walruses are hunted for their ivory.B: I see.A: Seals are bludgeoned to death to provide fur coats and the threat of extinction hangs over several species of whale, dolphin and porpoise.B: Really.A: We are now campaigning to provide sea sanctuaries for some of these endangered species.B: Very interesting.A: Aided by our campaign, protected nesting sites for turtles have already been set up. As you can see, this is very valuable work and I wonder therefore if you'd like to make a donation?Part2John James Audubon was an American artist in the early 1800s, who illustrated birds in their natural habitats. The Society named after him was founded in the late 1800s by conservationists concerned with the decline of birds, which were being killed so their feathers could be used in the manufacture of women's hats.Sponsored by the National Audubon Society, more than 40 000 volunteers will be outside counting birds from today until January 3rd. Volunteers from all 50 states of the United States, every Canadian province, parts of Central and South America, Bermuda, the West Indies and Pacific islands have begun to count and record every individual bird and bird species observed during the two and one half week period of the count.Jeffrey LeBaron is the National Audubon Society's Christmas Bird Count editor. He says the count is the longest-running bird census in ornithology.This year, according to Mr. LeBaron, more than 1 600 separate bird counts have been scheduled. Some would have as few as 10 people taking part, others with hundreds. The logistics of the Christmas bird count, he adds, are simple."Each individual count is in a circle. It's a 15 mile diameter circle, um, around the exact center point. And it's always the exactly same area that's done every year, usually, even on the same weekend during the count period. And what the ideal would be, which is virtually impossible, is this census: every single individual bird within that circle on the count day."Mr. LeBaron says experienced bird counters can get a good idea of the total bird populations within the count circle based on the number of birds they actually see. The editor points out, however, that the counts are not only for experienced bird watchers."Anybody that is interested or concerned can become involved. Beginners will go out in a party with experienced individuals who know both the area and the birds in the area, in the field where more eyes and ears are better. And then anybody can point out a bird, and someone in the field will always be able to identify the bird."Part3A —Alan Tu R — Rick Troud D — Deborah Duffield P — Peter Jones J — Jean Michel Coustea[Alan Tu is an announcer for Colorado Public Radio; Peter Jones is a reporter for Colorado Public Radio. The other speakers are identified in the report.]A: A planned aquatic park in Denver is raising the ire of animal rights activists who object to a proposal to include a captive dolphin display. Although officials for Colorado's Ocean Journeys say they have yet to make a final decision on the issue, local and national activists have already instigated a "No Dolphins in Denver' campaign. As Colorado Public Radio's Peter Jones reports, the battle lines have been clearly drawn.P: Rick Troud, a former navy dolphin trainer based in Florida, is taking an active role in the "No Dolphins" campaign.R: Average age in the wild ranges anywhere in some of the studies between 30 and 40 years of age. In captivity, you can expect a dolphin to live maybe 5.13 years, and every 7 years in captivity, the dolphin population is dead.P: According to Troud, there are many reasons why dolphins can't live full lives in captivity.R: If you take a look at where the real dolphin is in the real ocean, you find the dolphin who swims 40 miles a day, is very family-oriented. These animals are separated from their mothers; that's a stress. You put them in a concrete tank where their sonar bounces off of walls, they can't swim in the same amount of time and direction that they can in the wild.P: Environmentalist and ocean explorer, Jean Michel Cousteau:J: There are some animals which reject captivity right away, and they're very suicidal. I've had one of those in my own arms for many days. The next morning when I came to take care of him, he was dead. And what he'd done was to swim as fast as he could from one end of the pool on ... to the other side and destroyed his head by hitting the wall. They have a very sophisticated brain. I don't think we have any rights to play with the lives of these animals.P: Cousteau's anti-captivity position is challenged by Dr. Deborah Duffield, a biology professor at Portland State College in Oregon. Her 1990 study compared captive dolphins to the wild population of Sarasota Bay, Florida. Among other findings, the study showed little if any difference in the average age of death. And Duffield says life is generally getting better for captive dolphins.D: The census data say that every time I do a census, I've got older and older animals in it as well as this normal age distribution that we've been looking at. So my feeling is that the trend in captivity has been that the groups of animals that we’re following are getting older, and if they continue to do that over the next five years, they will then indeed be older than the wild population.P: There is also a debate over the educational benefits of keeping marine mammals in captivity. According to Duffield, captive dolphins play an important role in our basic understanding of the animals.D: I firmly believe that we cannot learn anything about organisms that we share this world with if we do not understand how they live in an environment, and what they do, and that watching them go by in the wild will not do it. I cannot tell what an animal needs, unless I know how it operates, how it breeds, what it needs metabolically, and I can't learn that from animals in the wild.P: But Troud says the dolphin displays are anti-educational because the animals' natural behavior patterns are altered by captivity.R: In the wild, you don't have dolphins who beat each other to death. There are no dolphins that I've ever seen stranded on the beach, who are suffering from fractured skulls, fractured ribs or fractured jaws, as is the case in captivity.P: The Ocean Journey board will take all factors into consideration before making a final decision on whether to include dolphins in the park. For Colorado Public Radio, I'm Peter Jones.Part4Mr. LeBaron says there are about 9 300 different known species of birds. Larger numbers of them live in the warmer climates. For example, more than 300 different species have been counted in Panama, while far fewer species are native to colder climates. Aside from their esthetic value, Mr. LeBaron says birds are important to the environment because they can signal changes in it."Birds are one of the best indicators that we have of the quality of the environment within the given area. Whether it is a relatively local area, or even primarily on the worldwide bases, they are one of the first things to be altered. They are quite sensitive to a habitat alteration or to other threats. And often times when birds are disappearing out of the area, it just means there is a degradation of the quality of the habitat within that area which will adversely affect everything in there including humans."National Audubon Society editor Jeffrey LeBaron calls the world's bird populations a source of wealth that humans must protect."People get so much pleasure out of looking at birds and listening to birds. And if they start disappearing just the er, the quality of life, um, may be not physically, but the mental quality of life can be degraded quickly."Jeffrey LeBaron says that while the National Audubon Society's annual Christmas bird counts show a decline in somespecies, many types of birds are actually increasing their populations.Part5Scientists have cataloged more than one and one-half million of the species that exist on Earth today. By some recent estimates, at least 20 times that many species inhabit the planet..Up to 100 species becomes extinct every day. Scientists estimate that the total number of species lost each year may climb to 40 000 by the year 2000, a rate far exceeding any in the last 65 million years..Around the world more than 3 500 protected areas exist in the form of parks, wildlife refuges and other reserves. These areas cover a total of about 2 million square miles (5 million square km, or 3% of our total land area)..Today, more than 200 animal species in the United States are classified as endangered. More than 1 000 animal species are endangered worldwide..Little-noticed aquatic animals are in big trouble. In North America, a third of our fish species, two-thirds of our crayfish species and nearly three-quarters of the mussel species are in trouble.------------------------------------------------------------------------------------------------------------------------Unit 3part1Looking here at Wednesday's weather forecast for Europe. It's certainly clear that winter is starting to take its grip on the continent. Berlin on Wednesday, mostly cloudy and very cold, and -2 degrees for your high. Brussels, Belgium, a little warmer at one degree, partly sunny. London, 5 degrees for your high, mostly cloudy throughout the day. In Paris, your high temperature is 0 degrees on Wednesday, partly cloudy as well. Rome, 8 degrees for your high, with periods of clouds and sunshine. And Vienna, Austria, -2 degrees on Wednesday, cloudy and of course cold. Athens, Greece, a little warmer at 10 degrees, periods of clouds and sunshine on Wednesday. Belgrade, Yugoslavia, 1 degree for your high, mostly cloudy. Istanbul, 5 degrees, and partly sunny. And Kiev, Ukraine, -7 degrees, and you can expect snow. Moscow, -9 degrees on Wednesday, also snowy. And in Prague, the Czech Republic, -4 degrees with snow flurries, so sounds like typical of weather for that area of the world. Let's look at what we have here in Washington D.C., no snow yet, but it will be coming.CAs 1998 ends and people look forward to the last year of the century, the World Almanac spoke with experts about what comes next. Almanac editorial director says the experts believe the next century will bring lots of changes."Warm, of course, that our climate is going to continue getting warmer. That's the subject, by the way, of another new article on the 1999 World Almanac. The greenhouse effect, exactly what causes it, and what steps to be taken to, um, perhaps, to alleviate global warmings. I've seen recently that 1998 is going to go down as the warmest year ever on record. And so that's going to be a major issue of the next century, and possible tremendous consequences of the global warmings, whether it is rising sea levels affecting the coastal areas; changes in climate zones affecting what crops can be grown, and in what regions. This is potentially a very significant trend to be watched."Major ocean storms in the northern part of the world usually develop in late summer or autumn over waters near the equator. They are known by several different names. Scientists call these storms cyclones when they happen just north or south of the equator in the Indian Ocean. In the western Pacific Ocean or the China Sea, these storms are called typhoons. In the eastern Pacific and Atlantic Ocean, they are called hurricanes.Part2Satellite readings confirm that conditions are right for another El Nino, a cyclic weather pattern that affects the global climate."El Nino's normally show up about twice a decade and it lasts about 12 to 18 months, bringing warmer weather to parts of the earth. Some regions become wetter than usual, others drier. The El Nino, which began in 1991 has lingered through this year. Although several years might have been expected to pass before the next one, an American-Frenchsatellite observing the oceans has found a sign that El Nino may come back quicker than expected."'These kinds of things still happen.' This is Brig Jacker, an oceanographer of the US Naval Research Laboratory in Mississippi."'Every year is unpredictable. One year might be El Nino year, one year might not. Generally El Nino's come in four year cycles. But there's nothing to say that you can't have two El Nino years in a row.'"El Nino's begin with the decline of winds pulling cold water away from South America's west coast to around the equator. This allows warm water in the western Pacific Ocean to expand eastward toward the America's. At the same time, the clouds and rain over the warm water move eastward too. Radar aboard the American-French satellite detected the hint thatsuch water movement began in early August and reached South America two months later. It saw a ripple called a 'Calvin wave' moving slowly eastward. Such pulses sometimes give rise to El Nino conditions in the eastern equatorial Pacific."El Nino's can change the weather around the world, but how much depends on its strength. A strong one in 1982 and 1983 has been linked to droughts in Australia and Indonesia, rains and flooding in South America, and unseasonably warm weather in much of the United States. But even the mild El Nino that began in 1991 has caused trouble. It has been associated with devastating floods in the US southeast last year and in the US midwest this year. El Nino's are hard on the South American fishing industry. The warm waters prevent nutrients rich cold water from rising to the surface, causing fish stocks to become depletive. Mr. Jacker said a new El Nino apparently would be mild but he is not betting on it yet."The US Naval oceanographer says predictions are difficult because the strength of El Nino depends on how winds affect the 'Calvin wave' that has moved across the Pacific."Part3It’s about an hour’s drive from the outskirts of San Jose, California, near the upper side of the state’s high-technology region known as “Silicon Valley”. As a visitor drives up the narrow winding road past red flowers, and eucalyptus trees, one of the first two seismographic stations in the world, it’s almost a surprise to glimpse the largest dom e of Lick Observatory’s eight telescopes. Overloo king the world of computer age manufacturing are telescopes from the turn of the century which help shape our understanding of the universe.The huge dome, housing Lick Observatory’s giant, one meter wide reflecting telescope, is one of the few instrume nts in motion this morning on Mount Hamilton. At the 1260-meter summit of Mount Hamilton is a small village of 55 permanent residents, some of them students in a one-room school house. But most at the research complex are visiting astronomers catching thei r first hours of sleep in an old dormitory after a night’s work at the telescopes. Reminton Stone, director of operations at Lick Observatory has worked at the top of Mount Hamilton for three decades. Now a part of the University of California, Lick Observatory got its name from a wealthy businessman who never studied astronomy as Mr. Stone explains: “And he came to San Francisco, just before the gold rush and he made a huge amount of money on real estate. When he died, he specified that some portion of his estate should be used to build the largest and most powerful telescope yet made and which was a 36 inch at that time. And at his own request he is buried at the base of the telescope. So this is a memorial to himself.”The telescope with its one-meter-diameter reflecting lens was the largest telescope in the world for seven years following its completion in 1888. And today, it’s still the second largest telescope of its kind. Although the one meter reflecting telescope is still used for some research, i t’s hard to adapt today’s electronic instruments to the old historic telescope. Now, it is used mostly as an educational tool for teachers and the thousands of visitors who come each year. While the other telescopes at Lick Observatory are connected to electronic imaging devices that allow the astronomers to view celestial objects on television screens, the 19th century telescope allows direct viewing with the human eye. It’s one of the few giant telescopes in the world that still requires some users to sit out in the cold under the dark sky and the dome. That brings a feeling of nostalgia to Reminton Stone.“I really do miss being able to see the sky, and seeing these wonderful data appear in the computer screen is really。