填空题[A] What route does HIV take after it enters the body to destroy the immune system?[B] How and when did the long-standing belief concerning AIDS and HIV crop up?[C] What is the most effective anti-HIV therapy?[D] How does HIV subvert the immune system?[E] In the absence of a vaccine, how can HIV be stopped?[F] Why does AIDS predispose infected persons to certain types of cancer and infections? In the 20 years since the first cases of AIDS were detected, scientists say they have learned more about this viral disease than any other. Yet Peter Plot, who directs the United Nations AIDS program, and Stefano gella of Rome, president of the International AIDS Society, and other experts say reviewing unanswered questions could prove useful as a measure of progress for AIDS and other diseases. Among the important broader scientific questions that remain: 41. ______ A long-standing belief is that cancer cells constantly develop and are held in check by a healthy immune system. But AIDS has challenged that belief. People with AIDS are much more prone to certain cancers like non-Hodgkins lymphomas and Kaposi's sarcoms, but not to breast, colon and lung, the most common cancers in the United States. This pattern suggests that an impaired immune system, at least the type that occurs in AIDS, does not allow common cancers to develop. 42. ______ When HIV is transmitted sexually, the virus must cross a tissue barrier to enter the body. How that happens is still unclear. The virus might invade directly or be carried by a series of different kinds of cells. Eventually HIV travels through lymph vessels to lymph nodes and the rest of the lymph system. But what is not known is how the virus proceeds to destroy the body's CD-4 cells that are needed to combat invading infectious agents. 43. ______ Although HIV kills the immune cells sent to kill the virus, there is widespread variation in the rate at which HIV infected people become ill with AIDS. So scientists ask: Can the elements of the immune system responsible for that variability be identified? If so, can they be used to stop progression to AIDS in infected individuals and possibly prevent infection in the first place? 44. ______ In theory, early treatment should offer the best chance of preserving immune function. But the new drugs do not completely eliminate HIV from the body so the medicines, which can have dangerous side effects, will have to be taken for a lifetime and perhaps changed to combat resistance. The new policy is expected to recommend that treatment be deferred until there are signs the immune system is weakening. Is a vaccine possible? There is little question that an effective vaccine is crucial to controlling the epidemic. Yet only one has reached the stage of full testing, and there is wide controversy over the degree of protection it will provide. HIV strains that are transmitted in various areas of the world differ genetically. It is not known whether a vaccine derived from one type of HIV will confer protection against other types. 45. ______ Without more incisive, focused behavioral research, prevention messages alone will not put an end to the global epidemic.

填空题C.P. Snow once said: "A sense of the future is behind all good policies. Unless we have it, we can give nothing either wise or decent to the world." Thinking carefully about an outcome is an intelligent first step in many processes, especially when the stakes are high, possibly even dangerous. Do you have any experience in getting out of hazardous situations? In the most exceptional circumstances, a few good rules of thumb may save you. Here are five things to keep in mind. 1 Stay calm If a catastrophe threatens your life, panic will only make matters worse. Nothing but calmness can help you adequately take stock of the situation and take appropriate measures. 2 Remain confident Desperation can paralyze you or sap your energy, while confidence is the key to saving yourself. 3 Help each other You should organize for mutual assistance in case of an earthquake, flood, fire, etc. People working together can always cope more successfully with any adverse situation. Solidarity means strength; solidarity means victory. 4 Be obedient to superiors The best strategy when facing a catastrophe is to obey commands and keep order. More often than not, leaders are experts, or someone familiar with the situation or with rich experience. Being too individualistic and going your own way will usually make the situation worse for you and others. So, the best thing to do is to listen to authorities and remain orderly. 5 Communicate When in danger it is best to seek help immediately so those with more resources can come to your aid. If you are at risk, use whatever, means available as soon as possible to contact others for help, and take efforts to maintain communication once it is established. While every catastrophe is different in its own way, all can be met and hopefully overcome with the above-mentioned pieces of advice. By carefully considering what needs to be done, even under the worst of situations, one can find solutions, or endure until aided by others. A. A person trapped in ruins in an earthquake, didn"t lose hope. The victim overcame his pain and despair, and kept banging out signals on the fallen wall around him for help. Because of his efforts, a rescue team was able to find him and save his life. B. For example, if numerous people are involved in a dangerous situation, some, out of fear or inclination, may not follow direction or heed sound advice. As a result of the disorder, rescue efforts are hindered, or worse more casualties are incurred. C. Nine fishermen from Peru were hit by a severe storm, but they didn"t panic even though their boat was damaged so badly that they couldn"t sail home. They maintained faith that they would surely to be saved, and their belief gave them strength. When there is hope, there is a way! They survived at sea for 40 days before they were finally rescued. Their story is a good sample for future people lost at sea. It is best to remember the proverb: God helps those who help themselves. D. History shows that when people are in danger mutual assistance promotes confidence, and reassuring others not only helps them, but can calm you as well. Helping others is beneficial, especially in the direst circumstances. During the Sept. 11 attacks in America, people pulled together and supported each other. This not only reduced casualties, but also left a deep impression on people around world. Remember, helping others is helping yourself. E. The Apollo 13 space mission suffered catastrophic mechanical problems en route to the Moon. Its malfunction was caused by an explosion and rupture of oxygen tank No. 2 in the service module. The NASA Mission Control Center immediately issued two orders. The second order was concerning navigation. But, can you guess what the first order was? Unbelievably, the astronauts were told to take two tranquillizer pills each! As a result, calmness helped the astronauts overcome a series of difficulties and return to earth. Calmness can work miracles in times of emergency. F. The best way to prevent a catastrophe from happening is planning ahead. You should often check your circuits, stoves, electrical appliances and gas pipelines. Before sleeping in a hotel, you should be aware of the nearest exit in case of an emergency. "Preparation averts peril."

填空题 Back when we were kids, the hours spent with friends were too numerous to count. There were marathon telephone conversations, all-night studying and giggling sessions. Even after boyfriends entered the picture, our best friends remained irreplaceable. And time was the means by which we nurtured those friendships. Now as adult women we never seem to have enough time for anything. Husbands, kids, careers and avocations-all require attention; too often, making time for our friends comes last on the list of priorities. And yet, ironically, we need our friends as much as ever in adulthood. A friendship network is absolutely crucial for our well-being as adults. We have to do the hard work of building and sustaining the network. Here are some important ways for accomplishing this. {{B}}Let go of your less central friendships.{{/B}} Many of our friendships were never meant to last a lifetime. It's natural that some friendships have time limits. Furthermore, now everyone has a busy social calendar, so pull back from some people that you don't really want to draw close to and give the most promising friendship a fair chance to grow. (41) {{B}}Be willing to "drop everything" when you' re truly needed. {{/B}} You may get a call from a friend who is really depressed over a certain problem when you are just sitting down to enjoy a romantic dinner with your husband. This is just one of those instances when a friend's needs mattered more. (42) {{B}}Take advantage of the mails. {{/B}} Nearly all of us have pals living far away-friends we miss very much. Given the limited time available for visits and the high price of phone calls, writing is a fine way to keep in touch-and makes both sender and receiver feel good. (43) {{B}}Risk expressing negative feelings. {{/B}} When time together is tough to come by, it's natural to want the mood during that time to be upbeat. And many people fear that others will think less of you if you express the negative feelings like anger and hurt. (44) {{B}}Don't make your friends' problems your own. {{/B}} Sharing your friend's grief is the way you show deep friendship.{{B}} Never underestimate the value of loyalty. {{/B}} Loyalty has always been rated as one of the most desired qualities in friends. True loyalty can be a fairly subtle thing. Some people feel it means that, no matter what, your friend will always take your side. But real loyalty is being accepting the person, not necessarily of certain actions your friend might take. (45) {{B}}Give the gift of time as often as time allows. {{/B}} Time is what we don't have nearly enough of-and yet, armed with a little ingenuity, we can make it to give it to our friends. The last but not the least thing to keep a friendship alive is to say to your friends "I miss you and love you." Saying that at the end of a phone conversation, or a visit, or writing it on a birthday card, can sustain your friendship for the times you aren't together. [A] But taking on your friend's pain doesn't make that pain go away. There's a big difference between empathy or recognizing a friend's pain, and over identification, which makes the sufferer feel even weaker-"I must be in worse pain than I even thought, because the person I'm confiding in is suffering so much!" Remember troubled people just need their friends to stay grounded in their own feelings. [B] Remember honesty is the key to keeping a friendship real. Sharing your pain will actually deepen a friendship. [C] Besides, letters, cards and postcards have the virtue of being tangible-friends can them and reread them for years to come. [D] The trick is remembering that a little is better than none and that you can do two things at once. For instance, if you both go for a weekly aerobics, go on the same day. If you both want to go on vocation, schedule the same destination. [E] Careful listening, clear writing, close reading, plain speaking, and accurate description-will be invaluable. In tomorrow's fast-paced business environment there will be precious little time to correct any misunderstandings. Communications breakdown may well become a fatal corporate disease. [F] Sometimes, because of our unbreakable commitments or other circumstances, we simply can't give a needy friend the time we'd like. If you can't be there at that given moment, say something like, "I wish I could be with you-I can hear that you're in pain. May I call you tomorrow?" Be sure your friend knows she's cared about.

填空题Recently, French taxi drivers paralysed Paris in protest against Uber, a ride-sharing service, and attacked a few Uber cars for good measure. From Uber"s point of view, all this is but a minor inconvenience: Paris is just one of 300 cities it serves. Far more worrying is what is happening in the company"s own backyard in San Francisco. The California Labour Commissioner ruled that Uber owes a former driver, Berwick, $ 4,152, mostly in expenses, on the ground that she was an employee rather than, as Uber claims, an independent contractor. 1 Uber is not the only big American company whose business model may be upended by employment law. Last year the National Labour Relations Board"s general counsel said he would treat McDonald"s as a joint employer, together with franchisees, of staff in the chain"s franchised restaurants. This opinion will soon be tested in a case brought by ten employees who claim that they were sacked by a franchisee in Virginia on racial grounds. 2 Uber has to confront state governments which stand to gain sizeable tax revenues if on-demand workers are classified as employees. McDonald"s has to wrestle with the Service Employees International Union, which has been trying for years to unionise fast-food restaurants. The legal situation seems to be murky in both cases. A pro-Uber lawyer could argue that the firm is essentially little more than a marketmaker that provides a forum for buyers and sellers of rides to come together. 3 Likewise, a pro-McDonald"s lawyer could argue that it is the franchisees who hire and fire workers, and who run the business from day to day. An anti-McDonald"s lawyer could point to the detailed rules that the company lays down on how workers in franchised restaurants are trained and how they should serve customers. 4 The post-war growth of franchising, and the expansion of companies that used freelance door-to-door sellers, began to blur the distinction. Now, the "on-demand" economy is all but obliterating it, by letting people sell their labour and rent out their assets—from cars to apartments—in a series of short-term assignments arranged by smartphone app. That the law is so dated suggests that judges should exercise as light a touch as possible. 5 Forcing McDonald"s to become a co-employer would expose those franchisees to coordinated union action and make it much more difficult for them to respond to local circumstances. A. Both Uber and McDonald"s are up against powerful interest groups that are capable of both fighting prolonged legal battles and playing on the public"s heartstrings. B. Uber"s drivers, and their peers at on-demand firms, would get expenses and other benefits if they were declared employees—but they would have less flexibility over working hours and, more important, the increased cost of employing them might mean fewer jobs. C. If the rulings go against the company, its labour costs may rise significantly, as it is forced to pay drivers" social security and other benefits as well as their expenses. Its valuation, which is currently above $ 40 billion, may suffer. D. The fundamental problem is that in America, as in many other rich countries, employment law has failed to keep up with the changing realities of modern work. In those days a far larger proportion of American men worked in manufacturing; most women did not work; and the difference between employees, who worked full-time for a company, and contractors, who were typically tradesmen such as plumbers, seemed much clearer. E. The most important thing to remember about the on-demand economy is that it has been a dramatic success not just for consumers but also for workers seeking flexibility. That is why Uber"s number of drivers has been doubling every six months for the past couple of years. F. The franchise model has thrived because it allows local entrepreneurs to join forces with a global goliath to scale up their businesses quickly while operating them according to local labour-market conditions. G. They are free to work for rivals, such as Lyft. An anti-Uber lawyer could retort that the company exercises considerable control over its workers. It screens them for criminal records, and weeds out those who get poor reviews from passengers.

填空题{{B}}Directions:{{/B}} You are going to read a text about The Big Melt, followed by a list of examples. Choose the best example from the list A-F for each numbered subheading (41-45). There is one extra example which you do not need to use. Mark your answers on ANSWER SHEET 1. Say goodbye to the world's tropical glaciers and ice caps. Many will vanish within 20 years. When Lonnie Thompson visited Peru's Quelccaya ice cap in 1977, he couldn't help noticing a school-bus-size boulder that was upended by ice pushing against it. Thompson returned to the same spot last year, and the boulder was still there, but it was lying on its side. The ice that once supported the massive rock had retreated far into the distance, leaving behind a giant lake as it melted away. Foe Thompson, a geologist with Ohio State University's Byrd Polar Research Center, the rolled-back rock was an obvious sign of climate change in the Andes Mountains. "Observing that over 25 years personally really brings it home," he says. "Your don't have to be a believer in global warming to see what's happening." 41. Thawed ice caps in the tropics. Quelccaya is the largest ice cap in the tropics, but it isn't the only one that is melting, according to decades of research by Thompson's team. No tropical glaciers are currently known to be advancing, and Thompson predicts that many mountaintops will be completely melted within the next 20 years. 42. Situation in areas other than the tropics. The phenomenon isn't confined to the tropics. Glaciers in Europe, Russia, new Zealand, the United States, and elsewhere are also melting. 43. The worsening effects of global warming. For many scientists, the widespread melt-down is a clear sign that humans are affecting global climate, primarily by raising the levels of carbon dioxide and other greenhouse gases in the atmosphere. 44. Receding ice caps. That's not to say that glaciers, currently found on every continent except Australia, haven't melted in the past as a result of natural variability. These rivers of ice exist in a delicate balance between inputs (accumulating snow and ice) and outputs (melting and "calving" of large chunks of ice). Over time, the balance can tilt in either direction, causing glaciers to advance or retreat. What's different now is the speed at which the scales have tipped. "We've been surprised at how rapid the rate of retreat has been," says Thompson. His team began mapping one of the main glaciers flowing out of the Quelccaya ice cap in 1978, using satellite images and ground surveys. 45. Thinning ice cores. And its' not just the margin of the ice cap that is melting. At Quelccaya and Mount Kilimanjaro, the researchers have found that the ice fields are thinning as well. Besides mapping ice caps and glaciers, Thompson and his colleagues have taken core samples from Quelccaya since 1976, when the ice at the drilling location was 154 meters thick. Thompson and his colleagues have also drilled ice cores from other locations in South America, Africa, and China. Trapped within each of these cores is a climate record spanning more than 8,000 years. It shows that the past 50 years are the warmest in history. The 4-inch-thick ice cores are now stored in freezers at Ohio State. On the future, says Thompson, that may be the only place to see what's left of the glaciers of Africa and Peru. [A] The latest report from the Intergovernmental Panel on Climate Change, prepared by hundreds of scientists and approved by government delegates from more than 100 nations, states. "There is new and stronger evidence that most of the warming observed over the last 50 years is attributable to human activities." The report, released in January, says that the planet's average surface temperature increased by about 0. 6℃ during the 20th century, and is projected to increase another 1.4℃ to 5.8℃ by 2100. That rate of warming is "with-out precedent during at least the last 10,000 years," says the IPCC. [B] Alaska's massive Bering and Columbia Glaciers located in nontropical regions, for example, have receded by more than 10 kilometers during the past century. And a study by geologists at the University of Colorado at Boulder predicts that Glacier National Park in Montana, under the influence of melting, will lose all of its glaciers by 2070. [C] For example, about 97 per cent of the planet's water is seawater. Another 2 per cent is locked in icecaps and glaciers. There are also reserves of fresh water under the earth's surface but these are too deep for us to use economically. [D] For example, Africa's Mount Kilimanjaro in tropical areas has lost 82 percent of its ice field since it was first mapped in 1912. That year, Kilimanjaro had 12.1 square kilometers of ice. By last year, the ice covered only 2.2 square kilometers. At the current rate of melting, the snows of Kilimanjaro that Ernest Hemingway wrote about will be gone within 15 years, Thompson estimates. "But it probably will happen sooner, because the rate is speeding up." [E] "I fully expect to be able to return there in a dozen years or so and see the marks on the rock where our drill bit punched through the ice," says Thompson. If that happens, it will mean that a layer of ice more than 500 feet thick has vanished into thin air. [F] The glacier, Qori Kalis, was then retreating by 4. 9 meters per year. Every time the scientists returned, Qori Kalis was melting faster. Between 1998 and 2000, it was retreating at a rate of 155 meters per years (more than a foot per day), 32 times faster than in 1978. "You can almost sit there and watch it move," says Thompson.

填空题 Back when we were kids, the hours spent with friends were too numerous to count. There were marathon telephone conversations; all-night studying and giggling sessions. Even after boyfriends entered the pictured our best friends remained irreplaceable. And time was the means by Which we nurtured those friendships. Now as adult women we never seem to have enough time for anything. Husbands, kids, careers and avocations--all require attention; too often, making time for our friends comes last on the list of priorities. And yet, ironically, we need our friends as much as ever in adulthood. A friendship network is absolutely crucial for our well being as adults. We have to do the hard work of building and sustaining the network. Here are some important ways for accomplishing this.{{B}} Let go of your less central friendships.{{/B}} Many of our friendships were never meant to last a lifetime. It's natural that some friendships have time limits. Furthermore, now everyone has a busy social calendar, so pull back from some people that you don't really want to draw close to and give the most promising friendship a fair chance to grow.{{B}} (41) Be willing to "drop everything" when you're truly needed.{{/B}} You may get a call from a friend who is really depressed over a certain problem when you are just sitting down to enjoy a romantic dinner with your husband. This is just one of those instances when a friend's needs mattered more.{{B}} (42) Take advantage of the mails.{{/B}} Nearly all of us have pals living far away--friends we miss very much. Given the limited time available for visits and the high price of phone calls, writing is a fine way to keep in touch and makes both sender and receiver feel good.{{B}} (43) Risk expressing negative feelings.{{/B}} When time together is tough to come by, it's natural to want the mood during that time to be upbeat. And many people fear that others will think less of you if you express the negative feelings like anger and hurt.{{B}} (44) Don't make your friends' problems your own.{{/B}} Sharing your friend's grief is the way you show deep friendship.{{B}} Never underestimate the value of loyalty.{{/B}} Loyalty has always been rated as one of the most desired qualities in friends. True loyalty can be a fairly subtle thing. Some people feel it means that, no matter what, your friend will always take you side. But real loyalty is being accepting the person, not necessarily of certain actions your friend might take.{{B}} (45) Give the gift of time as often as time allows.{{/B}} Time is what we don't have nearly enough of--and yet, armed with a little ingenuity, we can make it to give it to our friends. The last but not the least thing to keep a friendship alive is to say to your friends "I miss you and love you." Saying that at the end of a phone conversation, or a visit, or writing it on a birthday card, can sustain your friendship for the times you aren't together.[A] But taking on your friend's pain doesn't make that pain go away. There's a big difference between empathy or recognizing a friend's pain, and over identification, which makes the sufferer feel even weaker-- "I must be in worse pain than I even thought, because the person I'm confiding in is suffering so much!" Remember troubled people just need their friends to stay grounded in their own feelings.[B] Remember honesty is the key to keeping a friendship real. Sharing your pain will actually deepen a friendship.[C] Besides, letters, cards and postcards have the virtue of being tangible--friends can keep them and reread them for years to come.[D] The trick is remembering that a little is better than none and that you can do two things at Once. For instance, if you both go for a weekly aerobics, go on the same day. If you both want to go on vocation, schedule the same destination.[E] Careful listening, clear writing, close reading, plain speaking, and accurate description- will be invaluable. In tomorrow's fast-paced business environment there will be precious little time to correct any misunderstandings. Communications breakdown may well become a fatal corporate disease.[F] Sometimes, because of our unbreakable commitments or other circumstances, we simply can't give a needy friend the time we'd like. If you can't be there at that given moment, say something like, "I wish I could be with you I can hear that you're in pain. May I call you tomorrow?" Be sure your friend knows she's cared about.

填空题{{B}}Directions:{{/B}}You are going to read a list of headings and a text about science. Choose the most suitable heading from the list A—F for each numbered paragraph (41--45). The first paragraph of the text is not numbered. There is one extra heading which you don't need to use. Mark your answers on ANSWER SHEET 1. [A] The Need for Science[B] The Methods of Science[C] The Challenge of Unsolved Problems[D] The Specific Features of the Laws of Science[E] The Steps in Establishing a Scientific Theory[F] The Rapid Increase of Scientific Knowledge It is the business of the scientist to accumulate knowledge about the universe and all that is in it. and to find. if he is able. common factors which underlie and account for the facts that he knows. He chooses, when he can, the method of the "controlled experiment".41. ______. In the course of his inquiries the scientist may find what he thinks is one common explanation for an increasing number of facts. The explanation, if it seems consistently to fit the various facts, is called a hypothesis. If a hypothesis continues to stand the test of numerous experiments and remains unshaken, it becomes a law.42. ______. The "laws" of science differ from the "laws" of a country in two ways. First, a scientific law is liable at any time to need modifying. This happens when a fact is discovered which seems to contradict what the "law" would lead one to expect. The "law" may, in fact. have to be abandoned altogether. Second. a scientific "law" says, "This is likely to be the explanation", or "This accounts for the facts as far as we know them". But the "law" of the country says, "You must..." or "You must not..." The scientific "law" has no moral force; it is not binding on human behavior nor approved or opposed by human conscience.43. ______. The evidence as to the vastness of the universe and the complexity of its arrangements continues to grow at an amazing rate. The gap between what we know and all that can be known seems not to diminish, but rather to increase with every new discovery. Fresh unexplored regions are forever opening out. The rapidity of the growth of scientific knowledge, in the nineteenth and twentieth centuries, is apt to give students and teachers the impression that no sooner is a problem stated than the answer is forthcoming. A more detailed study of the history of science corrects the impression that fundamental discoveries are made with dramatic suddenness. Even in our present age no less than fifty years separate the discovery of radioactivity from the explosion of the first atomic bomb. The teacher, giving his brief accounts of scientific discovery, is apt to forget the long periods of misunderstanding, of false hypotheses and general uncertainty, which almost invariably precede the clear statement of scientific truth.44. ______. The vast mass of information which scientists have gained has provided the answer to the fundamental questions which, through the centuries, have puzzled and sometimes tortured the human mind. There are many such questions. The study of parasites has provided evidence that organisms which could be self-supporting have become parasites, but hardly any light has been shed on the problem of why they should have done so. What enables an organism to respond to the poisonous secretions of harmful bacteria and organize its resources to defend its life?45. ______. To raise the standard of living in any country, two things are required, scientific knowledge, and a population sufficiently educated to understand how to apply it. Without the latter, the expected benefits will not come. {{B}}Notes:{{/B}} ado 麻烦，忙乱。be binding on 对......有约束力。parasite 寄生虫。shed light on 使某事物更清楚些。 secretion 分泌物。

填空题 If you think you can make the planet better by clever shopping, think again. You might make it worse. You probably go shopping several times a month, providing yourself with lots of opportunities to express your opinions. If you are worried about the environment, you might buy organic food; if you want to help poor farmers, you can do your bit by buying Fairtrade products; or you can express a dislike of evil multinational companies and rampant globalization by buying only local produce. And the best bit is that shopping, unlike voting, is fun; so you can do good and enjoy yourself at the same time. Sadly, it's not that easy. {{U}}(41) {{/U}}. People who want to make the world a better place cannot do so by shifting their shopping habits: transforming the planet requires duller disciplines, like politics. Organic food, which is grown without man-made pesticides and fertilisers, is generally assumed to be more environmentally friendly than conventional intensive farming, which is heavily reliant on chemical inputs. But it all depends on what you mean by "environmentally friendly". Farming is inherently bad for the environment: since humans took it up around 11 000 years ago, the result has been deforestation on a massive scale. {{U}}(42) {{/U}}. Organic methods, which rely on crop rotation, manure and compost in place of fertiliser, are far less intensive. So producing the world's current agricultural output organically would require several times as much land as is currently cultivated. There wouldn't be much room left for the rainforest. Fairtrade food is designed to raise poor farmers' incomes. It is sold at a higher price than ordinary food, with a subsidy passed back to the farmer. But prices of agricultural commodities are low because of overproduction,{{U}} (43) {{/U}}. Surely the case for local food, produced as close as possible to the consumer in order to minimise "food miles" and, by extension, carbon emissions, is clear? Surprisingly, it is not. A study of Britain's food system found that nearly half of food-vehicle miles (i. e. , miles travelled by vehicles carrying food) were driven by cars going to and from the shops. Most people live closer to a supermarket than a farmer's market, so more local food could mean more food-vehicle miles. Moving food around in big, carefully packed lorries, as supermarkets do, may in fact be the most efficient way to transport the stuff What's more, once the energy used in production as well as transport is taken into account, local food may turn out to be even less green. {{U}}(44) {{/U}}. And the local-food movement's aims, of course, contradict those of the Fairtrade movement, by discouraging rich-country consumers from buying poor-country produce. But since the local-food movement looks suspiciously like old-fashioned protectionism masquerading as concern for the environment, helping poor countries is presumably not the point. {{U}} (45) {{/U}}. The problems lie in the means, not the ends. The best thing about the spread of the ethical-food movement is that it offers grounds for hope. It sends a signal that there is an enormous appetite for change and widespread frustration that governments are not doing enough to preserve the environment, reform world trade or encourage development.[A] The aims of much of the ethical-food movement--to protect the environment, to encourage development and to redress the distortions in global trade--are admirable.[B] By maintaining the price, the Fairtrade system encourages farmers to produce more of these commodities rather than diversifying into other crops and so depresses prices--thus achieving, for most farmers, exactly the opposite of what the initiative is intended to do.[C] Proper free trade would be by far the best way to help,poor farmers. Taxing carbon would price the cost of emissions into the price of goods, and retailers would then have an incentive to source locally if it saved energy.[D] There are good reasons to doubt the claims made about three of the most popular varieties of "ethical" food: organic food, Fairtrade food and local food.[E] But following the "green revolution" of the 1960s greater use of chemical fertiliser has tripled grain yields with very little increase in the area of land under cultivation.[F] And since only a small fraction of the mark-up on Fairtrade foods actually goes to the farmer--most goes to the retailer-the system gives rich consumers an inflated impression of their largesse and makes alleviating poverty seem too easy.[G] Producing lamb in New Zealand and shipping it to Britain uses less energy than producing British lamb, because fanning in New Zealand is less energy-intensive.

填空题[A]Itisalsousedtohelpstudentsgaintransitionskills:Studentswithautismordevelopmentaldelaycanvisitavirtualsupermarket,takepublictransportation,crossthestreet,ororganizehisorherday.Studentsinwheelchairscanlearnhowtonavigatebuildings.Andthebeautyis,thesestudentscanmakeanynumberofmistakeswithoutendangeringthemselves.[B]Forexample,virtualrealityhasbeenusedeffectivelytoassessstudents'depthperception,withtheresultsbeingquitedifferentfromthoseobtainedfromtraditionalpaperandpenciltests.[C]Thenwegraduallybeginshrinkingthesignandaddingotherenvironmentalelements.Oncethestudenthasmasteredthisvirtually,heorshetransferstheknowledgetotherealworld.Intheend,thisisthemostimportantfunctionofvirtualrealityprogramsforspecialstudents.[D]Virtualrealityevenallowsustotailortheworldtomeetachild'sneeds.Let'ssaywe'reteachingachildtocrossthestreetbypayingattentiontotrafficsigns.Educatorshavefoundthatitisoftendifficultforthechildtolocatethetrafficsigninabusyenvironment.Withvirtualreality,wecanblowupthe"walksign"sothestudentknowswhatitlookslike.[E]Anditisexpectedthatfutureteacherswillbeexposedtovirtualclasses,completewith"difficultstudents"tohelpthemmasterbehaviormanagementtechniques.[F]Infact,oneofthebiggestvirtuesofvirtualrealityisthatitallowsstudentstolearninasafeenvironment,andthisholdstrueforstudentswithbehaviordisorders.Afterastudenthaslearnedanappropriatebehaviororwayofcontrollinghisorheranger,thestudentisputinprogressivelymoredifficultvirtualsocialsituationswhereheorshecanpracticethenewtechnique.[G]Someoftoday'smostcutting-edgetechnologyisnowbeingusedtohelpstudentswithspecialneeds.Nolongerjusttheprovinceofgamesfor"videoneeds,"virtualrealityhascomeintoitsownasatoolforspecialeducationteachersandtherapists.Assuch,itisusedforassessment,teaching,andpractice,accordingtoSkipRizzo,researchassistant/professorattheUniversityofSouthernCalifornia.