单选题In many places water is becoming scarcer. Treating it as a right makes the scarcity worse. Ideally, efficient water use would be encouraged by charging for it, but attempts to do so have mostly proved politically impossible. A more practicable alternative is a system of tradable waterusage rights. As our explains, many water problems have global causes: population growth, climate change, urbanization and, especially, changing diets. It takes 2,000 liters of water to grow a kilo of vegetables but 15,000 liters to produce a kilo of beef—and people are eating more meat. The problems also have global implications. Without a new green revolution, farmers will need 60% more water to feed the 2 billion extra people who will be born between now and 2025. Yet there is, globally, no shortage of water. Unlike other natural resources (such as oil), water cannot be used up. It is recycled endlessly, as rain, snow or evaporation. On average, people are extracting for their own uses less than a tenth of what falls as rain and snow each year. The central problem is that so much water is wasted, mainly by farmers. Agri-culture uses three-quarters of the world"s water. Because water is usually free, thirsty crops like alfalfa (苜蓿) are grown in arid California. Wheat in India and Brazil uses twice as much water as wheat in America. Dry countries like Pakistan export textiles though a 1 kg bolt of cloth requires 11,000 liters of water. Any economist knows what to do: price water to reflect its value. But decades of trying to do that for agriculture have run into powerful resistance from farmers. They reject scarcity pricing for the reason that water falls from the skies. No government owns it, so no government should charge for it. There is a way out. Australian farmers have the right to use a certain amount of water free. They can sell that right to others. But if they want more water themselves, they must buy it from a neighbor. The result of this trading is a market that has done what markets do: allocate resources to more productive use. Australia has endured its worst drought in modern history in the past ten years. Water supplies in some farming areas have fallen by half. Yet farmers have responded to the new market signals by switching to less thirsty crops and kept the value of farm output stable. Water productivity has doubled. Australia"s system overcomes the usual objections because it confirms farmers" rights to water and lets them have much of it for nothing.

单选题According to the text, the decisive factor in maintaining a firm's competitive advantage is

单选题A mysterious "black cloud" approaches the earth -- our planet' s weather is severely affected. Throughout the rest of June and July temperatures rose steadily all over the Earth. In the British Isles the temperature climbed through the eighties, into the nineties, and moved towards the hundred mark. People complained, but there was no serious disaster. The death number in the U. S. remained quite small, thanks largely to the air - conditioning units that had been fitted during previous years and months. Temperatures rose to the limit of human endurance throughout the whole country and people were obliged to remain indoors for weeks on end. Occasionally air - conditioning units failed and it was then that fatalities occurred. Conditions were utterly desperate throughout the tropics as may be judged from the fact that 7943 species of plants and animals became totally extinct. The survival of man himself was only possible because of the caves and cellars he was able to dig. Nothing could be done to reduce the hot air temperature. More than seven hundred million persons are known to have lost their lives. Eventually the temperature of the surface waters of the sea rose, not so fast as the air temperature, it is true, but fast enough to produce a dangerous increase of humidity. It was indeed this increase that produced the disastrous conditions just remarked. Millions of people between the latitudes of Cairo and the Cape of Good Hope were subjected to a choking atmosphere that grew damper and hotter from day to day. All human movements ceased. There was nothing to be done but to lie breathing quickly as a dog does in hot weather. By the fourth week of July conditions in the tropics lay balanced between life and total death. Then quite suddenly rain clouds appeared over the whole globe. The temperature declined a little, due no doubt to the clouds reflecting more of the sun' s radiation back into space, but conditions could not be said to have improved. Warm rain fell everywhere, even as favorable as Iceland. The insect population increased enormously, since the burning hot atmosphere was as favorable to them as it was unfavorable to man and many other animals.

单选题Austerity is a word much found on the lips of politicians and economists at the moment; but it is seldom heard from technologists. And although the idea that "less is more" has many adherents in architecture, design and fashion, the technology industry has historically held the opposite view. Products should have as many features as possible; and next year's version should have even more. As prices fall, what starts off as a fancy new feature quickly becomes commonplace prompting companies to add new features in an effort to outdo their rivals. Never mind if nobody uses most of these new features. In an arms race, more is always more. But now there are signs that technologists are waking up to the benefits of minimalism, thanks to two things: feature fatigue among consumers who simply want things to work, and strong demand from less affluent consumers in the developing world. It is telling that the market value of Apple, the company most closely associated with simple, elegant high-tech products, recently overtook that of Microsoft, the company with the most notorious case of new-featuritis. Gadgets are no longer just for geeks, and if technology is to appeal to a broad audience, simplicity trumps fancy specifications. Another strand of techno-austerity can be found in software that keeps things simple in order to reduce distractions and ensure that computer-users remain focused and productive. Many word processors now have special full-screen modes, so that all unnecessary and distracting menus are disabled or hidden; rather than fiddling with font sizes or checking e-mail, you are encouraged to get on with your writing. A computer on which some features are not present, or have been deliberately disabled, may in fact be more useful if you are trying to get things done. There are no distracting hyperlinks on a typewriter. And then there is the phenomenon of "frugal" innovation--the new ideas that emerge when trying to reduce the cost of something in order to make it affordable to consumers in places like China, India and Brazil. The resulting products often turn out to have huge appeal in the rich world too, especially in an era of belt-tighten- ing. The netbook, or low-cost laptop, was inspired by a scheme to produce cheap laptops for children in poor countries, but has since proved popular with consumers around the world. All this offers grounds for hope. If the feature--obsessed technology industry can change its tune, perhaps there is a chance that governments--which have also tended to be habitual believers in the idea that more is more--might also come to appreciate the merits of minimalism.

单选题Seven years ago, a group of female scientists at the Massachusetts Institute of Technology produced a piece of research showing that senior women professors in the institute's school of science had lower salaries and received fewer resources for research than their male counterparts did. Discrimination against female scientists has cropped up elsewhere. One study conducted in Sweden, of all places--showed that female medical-research scientists had to be twice as good as men to win research grants. These pieces of work, though, were relatively small-scale. Now, a much larger study has found that discrimination plays a role in the pay gap between male and female scientists at British universities. Sara Connolly, a researcher at the University of East Anglia's school of economics, has been analyzing the results of a survey of over 7 000 scientists and she has just presented her findings at this year's meeting of the British Association for the Advancement of Science in Norwich. She found that the average pay gap between male and female academics working in science, engineering and technology is around ￡ 1 500 ($ 2850 ) a year. That is not, of course, irrefutable proof of discrimination. An alternative hypothesis is that the courses of men's and women's lives mean the gap is caused by something else; women taking "career breaks" to have children, for example, and thus rising more slowly through the hierarchy. Unfortunately for that idea, Dr. Connolly found that men are also likely to earn more within any given grade of the hierarchy, Male professors, for example, earn over ￡ 4 000 a year more than female ones. To prove the point beyond doubt, Dr. Connolly worked out how much of the overall pay differential was explained by differences such as seniority, experience and age, and how much was unexplained, and therefore suggestive of discrimination. Explicable differences amounted to 77% of the overall pay gap between the sexes. That still left a substantia123% gap in pay, which Dr. Connolly attributes to discrimination. Besides pay, her study also looked at the "glass-ceiling" effect--namely that at all stages of a woman' s career she is less likely than her male colleagues to be promoted. Between postdoctoral and lecturer level, men are more likely to be promoted than women are, by a factor of between 1.04 and 2.45. Such differences are bigger at higher grades, with the hardest move of all being for a woman to settle into a professorial chair: Of course, it might be that, at each grade, men do more work than women, to make themselves more eligible for promotion. But that explanation, too, seems to be wrong. Unlike the previous studies, Dr. Connolly's compared the experience of scientists in universities with that of those in other sorts of laboratory. It turns out that female academic researchers face more barriers to promotion, and have a wider gap between their pay and that of their male counterparts, than do their sisters in industry or research institutes independent of universities. Private enterprise, in other words, delivers more equality than the supposedly egalitarian world of academia does.

单选题The author argues that vaccinations are both a blessing and a curse because______.

单选题Chronic insomnia is a major public health problem. And too many people are using (1) therapies, even while there are a few treatments that do work. Millions of Americans (2) awake at night counting sheep or have a stiff drink or (3) an pill, hoping it will make them sleepy. (4) experts agree all that self-medicating is a bad idea, and the causes of chronic insomnia remain (5) . Almost a third of adults have trouble sleeping, and about 10 percent have (6) of daytime impairment that signal true insomnia. But (7) the complaints, scientists know surprisingly little about what causes chronic insomnia, its health consequences and how best to treat it, a panel of specialists (8) together by the National Institutes of Health concluded Wednesday. The panel called (9) a broad range of research into insomnia, (10) that if scientists understood its (11) causes, they could develop better treatments. Most, but not all, insomnia is thought to (12) other health problems, from arthritis and depression to cardiovascular disease. The question often is whether the insomnia came first or was a result of the other diseases and how trouble sleeping in (13) complicates those other problems. Other diseases (14) , the risk of insomnia seems to increase with age and to be more (15) among women, especially after their 50s. Smoking, caffeine and numerous (16) drugs also affect sleep. The NIH is spending about $200 million this year on sleep-related research, some (17) to specific disorders and others (18) the underlying scientific laws that control the nervous system of sleep. The agency was (19) the pane's review before deciding what additional work should be (20) at insomnia.

单选题The role of governments in environmental management is deficit but inescapable. Sometimes, the state tries to manage the resources it owns, and does so badly. Often, (1) , governments act in an even more harmful way. They actually subsidize the exploitation and (2) of natural resources. A whole (3) of policies, from farm-price support to protection for coal-mining, do environmental damage and often (4) no economic sense. Making good policies offers a two-fold (5) : a cleaner environmentpolilicians and a more efficient economy. Crowth and environmentalism can actually go hand in hand, if politicians have the courage to (6) the vested interest that subsidies create. No activity affects more of the earth's surface than farming, h shapes a third of the planet's land area, not (7) Antarctica, and the proportion is rising. World food output per head has risen by 4 percent between the 1970s and 1980s mainly as a result of increases in (8) from land already in (9) , but also because more land has been brought under the plough. Higher yields have been achieved by increased irrigation, better crop breeding, and a (10) in the use of pesticides and chemical fertilizers in the 1970s and 1980s. All these activities may have (11) environmental impacts. For example, land clearing for agrieuhure is the largest single (12) of deforestation; chemical fertilizers and pesticides may (13) water supplies; more intensive farming and the abandonment of fallow periods (14) worsen soil erosion; and the spread of monochord and use of high-yielding varieties of euros have been accompanied by the (15) of old varieties of food plants which might have provided some (16) against pests or diseases in future. Soil erosion threatens the productivity of land in both rich and poor countries. The United States, (17) the most careful measurements have been done, discovered in 1982 that about one-fifth of its farmland was losing topsoil at a rate (18) to diminish the soil's productivity. The country subsequently (19) a program to convert 11 percent of its cropped land to meadow or forest. Topsoil in India and China is (20) much faster than in America.

单选题In para. 4 the author uses an example to show______.

单选题The most probable reason for some children backward in speaking is______

单选题{{B}}Text 2{{/B}} Teachers grumble over pay everywhere, but in West Virginia Wesleyan College the anger is acute. Salaries here have barely moved since 2000, and the average assistant professor's pay has fallen below that at Southern West Virginia Community and Technical College. On a campus with just 86 full-time faculty, a sociology professor said, a few hundred thousand dollars more spent on teaching could make a real difference. Wesleyan President William Haden says the college plans to raise faculty pay. But he says Wesleyan is nothing without students -- "they vote with their feet" -- and the college has no choice but to address their wants and needs. He says technology has been a big part of that, and some recent graduates agree that it's valuable -- though maybe not essential. Daniel Simmons, a 1999 graduate and also a middle-school teacher, praised the technology program. "If I had gone to another school it wouldn't have been available to me," he said. "It was very convenient and it was top of the line." But as with the faculty, the quality of human instructors is a big concern among Wesleyan alumni. "A little bit more money should have been put into keeping people," said Evan Keeling, a 2002 graduate now pursuing a doctorate at the University of Virginia. He found the quality in the classroom uneven, and, notably, neither he nor the Daniel Simmons came to Wesleyan because of technology. The program was a bonus, not the primary draw. Skinner, the director of admission and financial planning, acknowledged that seems widely true. Prospective students pay more attention to more tangible signs of growth. "It did open some doors for us, but would I have liked to have had a new residence hall or recreational facility? I probably would have preferred that," Skinner said. His daily. struggle remains filling the freshman class, which may be down 50 people or more this year, due to changes in government financial aid programs and the shuttering of the nursing program. The college still accepts about 80 percent of its applicants, and no longer requires online applications. Haden acknowledges that, with the benefit of hindsight, he might have handled details of how the program was financed differently. But he makes no apologies for taking bold steps which he says have indeed set Wesleyan apart. "We needed to make a statement about our commitment to technology and our belief that it would enhance the quality of education and the preparation of our students," he said. "And I'm still believing that."

单选题The wise man's remarks suggest that______