全新版大学英语视听阅读2-Unit1-5.doc

Unit 1Watchingvideo SCRIPTNarrator: The cheetah. With an astonishing ability to sprint from zero to eighty kilometers per hour in just three seconds, its the fastest animal on land. At full speed, it can reach almost 100 kilometers per hour. Nothing can escape a cheetah at full sprint. Unfortunately, this beautiful, shy animal is in serious danger of becoming extinct. In order to help, National Geographic is sending a team into the Moremi Wildlife Reserve of Botswana. Their goal is to help save these magnificent creatures by capturing them on film.The city of Johannesburg, South Africa, is the final stop before the teams journey into the wilds of Africa. Heading the expedition is Chris Johns, a photographer for more than 25 years. Chris has been planning this trip for a long time, and accompanying him is guide Dave Hamman. Dave has lived in southern Africa most of his life and knows the region well. His knowledge will be useful as the two men head more than 800 kilometers north into Botswana and the wonderful Okavango Delta.The Moremi Reserve is a truly magical place. It seems that Africas entire animal kingdom resides in the region. Zebras, buffaloes, and elephants are easily viewed from the rough dirt road. Even a giraffe makes an appearance. Chris and Dave continue their drive into the evening. They need to be far into the wilderness to begin their task: finding cheetahs. Narrator: The next day, theyre up early to begin their search.Chris Johns, National Geographic Photographer: “You cant just drive out there and order up a cheetah. It doesnt happen like that. You know that it could take days, weeks.”Narrator: But then something incredibly unexpected occurs . . .Dave Hamman: “I dont believe this.”Narrator: Its a female and five of her young.Hamman: “This is just not normal.”Narrator: During all of his years in the bush, Dave has never located so many cheetahs this quickly. This is exactly what they had been hoping for. The discovery is especially promising for Chris.Johns: “Cheetahs are a metaphor for some of Africas conservation problems. Because cheetahs need range, and theyre a good way to explain to people that loss of habitat means the potential loss of species. And its possible that in my lifetime cheetahs could become extinct in the wild, and thats to me a tragedy thats unspeakable.”Narrator: The Moremi Wildlife Reserve has offered Chris one of the last windows into the natural world of the cheetah. It will take a while for the cheetahs to trust Chris, but if he succeeds, he knows hell be able to take the photographs he really wants: a shot of a cheetah pursuing and killing its prey, or a “kill sequence.”Johns: “We know there are certain things that a cheetah story has to have. One of the most important things it has to havewhich is an incredibly difficult thing to getis a kill sequence, and youre always looking for that picture.”Narrator: Cheetahs are capable of tremendous bursts of speed, and have the capacity to gain speed more quickly than a sports car. However, while they can reach almost 100 kilometers an hour, cheetahs cant maintain such speeds for more than 200 to 300 meters.The cheetahs failed to catch her dinner this time. Cheetahs must make a kill every few days. After missing the reedbuck, the mother is exhausted, and her cubs are still hungry. The two men drive back to camp, leaving the cheetah family to rest in the shade.Narrator: The next day, Chris and Dave return to where they last saw the family and find that the mother and her cubs are gone. The female has probably taken the cubs away to protect them. They must now look for the cheetahs all over again.Johns: “We still havent seen the mother with five cubs for several days now. The challenge is to keep your concentration, to constantly look. I mean, were looking for at least eight to ten hours a day.”Narrator: The tiring and difficult search turns from days into a week. The two men scan everything from heavy bushes to open grasslands, hoping to catch sight of the mother. Then, suddenly, their efforts become worth it.Hamman: “There! Lets go, lets go!”Johns: “Did you see her?”Hamman: “Yeah! Shes in the grass, just down, just down the break . . .”Narrator: Theyve found her and she looks fine. Chris must now wait to see if the mother cheetah will let him back into her trust so that he can photograph her. Only she can decide if and when.Chriss opportunity for shooting a kill sequence presents itself later in the morning. Suddenly, the mother sits up, watching and listening carefully. Shes seen something: two reedbucks.Johns: “Twelve o clock. Two reedbucks, twelve o clock.”Narrator: With her cubs hidden safely away, the brave hunter moves toward her target.Johns: “There she goes! There she goes!”Hamman: “Hang on!”Narrator: The men must drive as quickly as possible in order to get the shot.Johns: “She just moved. Did you see her? Hang on. She nailed it. Got em! Good job, girl. Well done! Shes a good hunter. Shes a real good hunter.”Narrator: In typical cheetah style, the mother chokes her prey. Then, she takes time to recover from her sprint.Johns: “Its a vulnerable time because if a hyena or another predator moved in on her, she could be ambushed. She is going to be very cautious.”Narrator: Satisfied for the moment that no other predators are in the area, the female calls her cubs to join her for their meal.Johns: “Its lunchtime . . .”Narrator: The mother and cubs are finally trusting Chris more than he ever expected.Johns: “Its amazing that the cheetahs are letting me this close. These are the pictures Ive been waiting for for ten years.”Hamman: “You only see things like this if youre extremely lucky, but also patient. How many hours have we spent with these cheetahs now to actually get this far? You know, you just have to put in the time to get the results.”Narrator: Finally, all of their patience has brought the expedition the results they had been waiting to achieve, but theres still one more surprise for them . . .Each day, mother and cubs open up more to the humans, and allow them to get closer. Then finally, something truly wonderful happens.Johns: “That was a fantastic experience, for me one of the highlights of my life. But I think with that experience goes a lot of responsibility on my part.”Narrator: Chris now feels that he has a special responsibility. He wants to communicate the endangered status of these beautiful animals to the world both through his photographs and the National Geographic article.Johns: “Shes just given me a tremendous privilege, one of the finest privileges of my life. So with that privilege goes a great deal of responsibility, I think, on my part.”Narrator: Hopefully, Chris can fulfill this responsibility by bringing the endangerment of these animals into worldwide focus. Maybe his actions will help save the cheetahs of the Okavango, and the world.HOME LISTENINGaudio SCRIPTUnderstanding Extinction A species is considered extinct when careful scientific surveys show that the last individual of that species has died. The loss of many species of plants and animals has been attributed to changes in climate, genetic weaknesses, and human activities such as hunting and environmental destruction. Studies have shown that almost all living things will eventually become extinct. In fact, more than 99 percent of the species that have ever lived on Earth have now disappeared permanently. Although this sounds like a terrible situation, it is important to understand that the earth seems to recover from the loss of great numbers of species. In many cases, replacement species emerge over time; however, extinction does decrease the diversity of life on the planet in the short term. These replacement species often require recovery periods of millions of years. Human beings have had a huge impact on the extinction rates of various species. Therefore, scientists have recently begun to examine humankinds effects on the numbers of species that have become extinct. Through the use of geographical and biological research, a “background extinction rate” has been established. These figures show the numbers of species which have disappeared during specific time periods. By comparing rates of extinction before and after human existence, researchers were able to discover the exact effects of humankind on nature. Studies now cite that the extinction rates after human life began are 100 to 1,000 times greater than before human influence on Earth. Future rates are forecasted to be even higher. This demonstrates the tremendous negative impact that human activity is having on extinction rates. Scientists are currently researching methods of dealing with this astonishing trend. As individuals, educators, and governments try to manage species survival, one key factor they find is that without help, some of the worlds species cannot survive. In addition, scientists must learn to make difficult decisions based on incomplete information. They must also deal with groups that may have a vested interest in not protecting certain species. For example, people interested in developing oil fields in the Arctic may not think the protection of the wildlife in the region is of primary importance.Unit 2Watchingvideo SCRIPTNarrator: Near the edge of the Arctic region of Canada, the short summer is being chased away by a constant cold wind from the north. Along the western shore of the Hudson Bay, winter is beginning to close its grip. One animal, with its thick fur and layer of heavy blubber, actually thrives in these freezing, lonely surroundings: the polar bear.Cam Elliot, Manitoba Conservation: “Polar bears are built for winter. Theyre built for the cold. Theyre built for the wind.”Narrator: These marine mammals spend most of their lives on frozen seas, and they depend on the frozen ice packs for hunting. But these polar bears dont enjoy the luxury of an uninterrupted winter.Elliot: “With the onset of summer and the warmer temperatures, all of Hudson Bay melts. Unlike the high Arctic, theres no permanent ice pack here. When the Bay melts, the bears are forced to shore.”Narrator: Its a seasonal life for the bears and when the weather starts to turn cold again, large numbers of them gather around the coast. At this time, these typically private animals will interact in ways not completely understood by humans, all the while waiting for the Bay to freeze so they can go back to the ice and their food source. As the bears wait, they often have company. These “tundra buggies” are designed to bring people to the polar bears.Nikita Ovsyanikow, Biologist: “Well, its an adult male, but rather young. Hes not in bad shape.”Narrator: No other animal hunts the polar bear; theyre at the top of the food chain. Therefore, they are considered good indicators of the health of the Arctic environment.Ovsyanikow: “What is especially attractive in polar bears in terms of conservation, it is a well . we say “umbrella species”. Its a large predator which is the top of food chains in the Arctic.”Narrator: At this time of year, the polar bears have used up the built-up fat reserves that have kept them alive since the ice melted.John Bykerk, Polar Bear Guide: “Theyre hungry. Unless theyre lucky enough to find some dead beluga whale or dead seal, perhaps thats washed up on shore. Theyve essentially gone four months at this point without having a bite to eat.”Narrator: Many researchers believe that the health of polar bears parallels the health of the environment. Scientists are concerned that despite the constant cold in Northern Manitoba, it may not be staying cold long enough to keep the environment stable. Global warming may be affecting the ice patterns, which are critical for the survival of the worlds largest land carnivore.Elliot: “Over the last twenty-five years, research conducted by the Canadian Wildlife Service has found about a two-week advancement in spring weather and ice melt. Polar bears are a creature of the sea ice. When theyre out on the ice, theyre hunting seals. Anything in global climate that would affect the stability or the length of the time that the ice is on the Hudson Bay or the Arctic waters, is going to have immediate impact on polar bears.”Narrator: Polar Bear Guide John Bykerk is also concerned about the impact of global warming on the bears. He reports that in a recent year, ice didnt form on Hudson Bay until around December 12th. The bay normally freezes around November 19th. As a result, the bears lost two or three weeks of feeding at the beginning of the season. He also reports that the ice thawed early in the spring of the next year, so the bears lost another two or three weeks. In total, the bears lost four to six weeks of hunting, which significantly affected their ability to find enough food.Narrator: Nikita Ovsyanikow has studied polar bears for years, and believes they are a key to understanding the Arctic.Ovsyanikow: “When we focus on polar bears, and develop any consideration measures for polar bears, the consequence of that is that we are protecting the entire Arctic ecosystem.”Narrator: For most people, polar bears truly symbolize the frozen North of our Earth. Its hard to imagine the Arctic or the world without them. Can the world afford to lose the beautiful polar bear? Will people do something to ensure that they survive? The future of one of the Arctics most majestic creatures lies in the answers to these questions, and in the conservation efforts of a caring world. HOME LISTENINGaudio SCRIPTClimate Change: Not Only a Human WorryBy Margaret BenningNew York, June 4 In the past century, the earths temperature has risen by approximately 0.6 to 0.8 degrees Celsius. Scientists believe that this is the result of an enhanced greenhouse effect, which is the process by which the earth maintains its temperature. Recently, a rise in certain types of gases, such as carbon dioxide (CO2), has increased the amount of heat trapped near the earths surface by the effect. This increase has resulted in an insulating and warming of the planet. These problematic gases, or “greenhouse gases”, come from car and truck exhaust, factory smoke, and the burning of certain substances for heat and light. If alternative methods of producing energy are not found soon, the earths temperature will likely rise between 1.4 and 5.8 degrees Celsius by the end of the 21st century. Extreme temperature changes, such as those projected over the next 100 years, could be a serious threat to the human environment. However, the effects of global warming will most likely appear in animal populations first. In fact, certain changes have already been observed. For example, early thaws in the ice of the Bering Sea have affected the mating season of several types of seals. Certain species of birds are changing their nesting patterns as well. Certain plants are flowering earlier, and other large animals are changing their annual periods of sleeping and waking. According to Stanford University, global warming has directly resulted in biological changes to 1,473 species around the world. Environmental groups, both governmental and private, are currently working to decrease the amount of dangerous gases, or “emissions”, released each year. One of the first international gatherings organized by the United Nations to approach the problem produced a document which eventually became known as the “Kyoto Protocol”. Its aim was to stabilize greenhouse gas levels to prevent dangerous changes in the worlds climate. The agreement set limits on the amounts of greenhouse gases that each participating nation could release each year. Unfortunately, the agreement didnt include strict enforcement procedures for implementing the program, and as of 2008, several countries only participate in the plan on a reporting basis. Others, including the United States, have refused to sign the document.Unit 3Watchingvideo SCRIPTNarrator: In a small village in Provence, France, residents have gathered to give thanks. While they sing and pray to Saint Anthony, these church members are praying for something different: a good truffle harvest. At the annual truffle mass, the collection plate is filling up, and not just with cash. In Richerenches, truffles are sometimes called “black diamonds”. At a price of up to $1,000 U.S. per pound, theyre one of the worlds most expensive foods. The name Richerenches means “rich earth”, appropriate for this village. Half of Frances black truffles are transported through the towns market, up to $180,000 U.S. worth a day. Theyre all looking for truffles, and not just any one will do, either.Pierre-Andre Valayer, Truffle Broker: “Its a most important market of truffles in France. So if you want to buy some truffle, you have to be in Richerenches to buy something. So for the sellers, its the same thing. If you want to sell well, they have to come to Richerenches.”Narrator: Provence generally brings to mind summer holidays, lazy afternoons, and ancient customs. In winter though, the small towns pace speeds up considerably. Many of the regions farmers also work as truffle hunters. Most of the business is done discretely from the backs of the brokers cars. One small bag of truffles is worth hundreds of U.S. dollars, so the trade is certainly lucrative.Philippe Oger, Truffle Eater: “I do think they buy apartments and so on . . . on the Riviera with this money. I know that.”Narrator: The buying and selling of truffles is mainly a cash business, its usually under the table. This means that the brokers often dont pay any taxes on the money they earn and neither do the hunters. Most people presume th