单选题 Smart Window Windows not only let light in to cut down an electricity use for lighting, but the light coming through the window also provides heat. However, windows are not something people typically associate with being a cutting edge technology. Researchers are now working on new technologies that enable a window to quickly change from clear to dark and anywhere in between with a flip of a switch. "It took us a long time to figure out what a window really is," says Claes Granqvist. He's a professor of solid-state physics at Uppsala University in Sweden. "It's contact with the outside world. You have to have visual contact with the surrounding world to feel well." So, windows and natural light are important for improving the way people feel when they're stuck indoors. Yet, windows are the weak link in a building when it comes to energy and temperature control. In winter, cold air leaks in. When it's hot and sunny, sunlight streams in. All of this sunlight carries lots of heat and energy. And all of this extra heat forces people to turn on their air conditioners. Producing blasts of cold air, which can feel so refreshing, actually suck up enormous amounts of electricity in buildings around the world. Windows have been a major focus of energy research for a long time. Over the years, scientists have come up with a variety of strategies for coating, glazing, and layering windows to make them more energy efficient. Smart windows go a step further. They use chromogenic technologies which involve changes of color. Electrochromic windows use electricity to change color. For example, a sheet of glass coated with thin layers of chemical compound such as tungsten oxide works a bit like a battery. Tungsten oxide is clear when an electric charge is applied and dark when the charge is removed, that is, when the amount of voltage is decreased, the window darkens until it's completely dark after all electricity is taken away. So applying a voltage determines whether the window looks clear or dark. One important feature that makes a smart window so smart is that it has a sort of "memory". All it takes is a small jolt of voltage to turn the window from one state to the other. Then, it stays that way. Transitions take anywhere from 10 seconds to a few minutes, depending on the size of the window. The development of smart windows could mean that massive air conditioning systems may no longer need. "In the future," Granqvist says, "our buildings may look different."

单选题The police took fingerprints and identified the body.

单选题Eat Healthy "Clean your plate!" and "Be a member of the clean-plate club!" Just about every kid in the US has heard this from a parent or grandparent. Often, it"s accompanied by an appeal: "Just think about those starving orphans in Africa!" Sure, we should be grateful for every bite of food. Unfortunately, many people in the US take too many bites. Instead of staying "clean the plate", perhaps we should save some food for tomorrow. According to news reports, US restaurants are partly to blame for the growing bellies. A waiter puts a plate of food in front of each customer, with two to four times the amount recommended by the government, according to a USA Today story. Americans traditionally associate quantity with value and most restaurants try to give them that. They prefer to have customers complain about too much food rather than too little. Barbara Rolls, a nutrition professor at Pennsylvania State University, told USA Today that restaurant portion sizes began to grow in the 1970s, the same time that the American waistline began to expand. Health experts have tried to get many restaurants to serve smaller portions. Now, apparently, some customers are calling for this too. The restaurant industry trade magazine QSR reported last month that 57 percent of more than 4, 000 people surveyed believe restaurants serve portions that are too large; 23 percent had no opinion; 20 percent disagreed. But a closer look at the survey indicates that many Americans who can"t afford fine dining still prefer large portions. Seventy percent of those earning at least $150, 000 per year prefer smaller portions; but only 45 percent of those earning less than $25, 000 want smaller. It"s not that working class Americans don"t want to eat healthy. It"s just that, after long hours at low-paying jobs, getting less on their plate hardly seems like a good deal. They live from paycheck to paycheck, happy to save a little money for next year"s Christmas presents.

单选题Engineers use the principles of aerodynamics in designing airplanes and other objects affected by aerodynamic forces. A. laws B. movements C. studies D. products

单选题For the time being, it is not a bad choice.A. nearlyB. presentlyC. lastlyD. temporarily

单选题Some stretches of Florida resemble West Africa.A. deal withB. look likeC. allow immigration fromD. look down upon

单选题Medical facilities are being {{U}}upgraded{{/U}}. A. expanded B. repaired C. improved D. transferred

单选题That one mistake ruined his chances of getting the job.A. reducedB. destroyedC. deniedD. lost

单选题{{B}}第二篇{{/B}} {{B}}New U.S. Plan for Disease Prevention{{/B}} Urging Americans to take responsibility for their health, Health and Human Services Secretary Tommy Thompson on Tuesday launched a $15 million program to try to encourage communities to do more to prevent chronic diseases like heart disease, cancer and diabetes (糖尿病). The initiative highlights the costs of chronic diseases—the leading causes of death in the United States—and outlines ways that people can prevent them, including better diet and increased exercise. "In the United States today, 7 of 10 deaths and the vast majority of serious illness, disability and health care costs are caused by chronic diseases," the Health and Human Services department said in a statement. The causes are often behavioral--smoking, poor eating habits and a lack of exercise. "1 am convinced that preventing disease by promoting better health is a smart policy choice for our future," Thompson told a conference held to launch the initiative. "Our current health care system is not structured to deal with the rising costs of treating diseases that are largely preventable through changes in our lifestyle choices." Thompson said heart disease and strokes will cost the country more than $351 billion in 2003. "These leading causes of death for men and women are largely preventable, yet we as a nation are not taking the steps necessary for us to lead healthier, longer lives," he said. The $15 million is designed to go to communities to promote prevention, pushing for changes as simple as building sidewalks to encourage people to walk more. Daily exercise such as walking can prevent and even reverse heart disease and diabetes, and prevent cancer and strokes. The money will also go to community organizations, clinics and nutritionists who are being encouraged to work together to educate people at risk of diabetes about what they can do to prevent it and encourage more cancer screening. The American Cancer Society estimates that half of all cancers can be caught by screening, including Pap tests (巴氏试验) for cervical (子宫颈) cancer, mammograms (乳房×线照片) for breast cancer, colonoscopies (结肠镜检查), and prostate (前列腺的) checks. If such cancers were all caught by early screening, the group estimates that the survival rate for cancer would rise to 95 percent.

单选题A portion of an employee's wages is withheld by the employer for income taxes.A. borrowedB. retainedC. guaranteedD. paid

单选题In a 1960 study, children were shown drawings of children with disabilities and without them, and a drawing of an obese child. They were asked which they would want for a friend. The obese child was picked last. Three researchers recently repeated the study using college students. Once again, almost no one, not even obese people, liked the obese person. "Obesity was stigmatized," the researchers said. Who was/were picked last by the subjects as a friend in both studies?A. People with disabilities.B. Average people.C. Obese people.D. People like themselves.

单选题{{B}}第二篇{{/B}} CT Scans and Lung Cancer Small or slow-growing nodules (小结节) discovered on a lung scan are unlikely to develop into tumors over the next two years, researchers reported on Wednesday. The findings, reported in the New England Journal of Medicine, could help doctors decide when to do more aggressive testing for lung cancer. They could also help patients avoid unnecessarily aggressive and potentially harmful testing when lesions (损伤) are found. Lung cancer, the biggest cancer killer in the United States and globally, is often not diagnosed until it has spread. It kills 159,000 people a year in the United States alone. The work is part of a larger effort to develop guidelines to help doctors decide what to do when such growths, often discovered by accident, appear in a scan. High-tech (高技术的) X-rays called CT scans can detect tumors -- but they see all sorts of other blobs (糊涂的一团) that are not tumors, and often the only way to tell the difference is to take a biopsy (活检), a dangerous procedure. At the moment, routine lung cancer screening is considered impractical because of its high cost and because too many healthy people are called back for further testing. Good guidelines could help make lung cancer screening practical, Dr. Rob van Klaveren of the Erasmus Medical Center in Rotterdam, the Netherlands, who led the new study, said in a telephone inter view. The team looked at 7,557 people at high risk for lung cancer because they were current and former smokers. All received multidetector (多层螺旋) CT scans that measured the size of any suspicious-looking nodules. Volunteers who had nodules over 9.7 mm in width, or had growths of 4.6 mm that grew fast enough to more than double in volume every 400 days, were sent for further testing. Of the 196 people who fell into that category, 70 were found to have lung cancer; 10 additional cases were found years later. But of the 7,361 who tested negative during screening, only 20 lung cancer cases later developed. In a second round of screening, done one year after the first', 1.8 percent were sent to the doctor because they had a nodule that was large or fast-growing. More than half turned out to have lung cancer. The result means that if the screening test says you don't have lung cancer, you probably don't, the researchers said. "The chances of finding lung cancer one and two years after a negative first-round test were 1 in 1,000 and 3 in 1,000 respectively," they concluded.

单选题Burke and Hare differed from other body snatchers in that

单选题The Best Way to Reduce Your Weight You hear this: "No wonder you are fat. All you ever do is eat." You feel sad: "I skip my breakfast and supper. I run every morning and evening. What else can I do?" Basically you can do nothing. Your genes, not your life habits, determine your weight and your body constantly tries to maintain it. Albert Stunkard of the University of Pennsylvania found from experiments that, "80 percent of the children of two obese (肥胖的) parents become obese, as compared with no more than 14 percent of the offspring of two parents of normal weight." How can obese people become normal or even thin through dieting? Well, dieting can be effective, but the health costs are tremendous. Jules Hirsch, a research physician at Rockefeller University, did a study of eight fat people. They were given a liquid formula providing 600 calories a day. After more than 10 weeks, the subjects lost 45kg on average. But after leaving the hospital, they all regained weight. The results were surprising: by metabolic (新陈代谢的) measurement, fat people who lost large amounts of weight seemed like they were starving. They had psychiatric problems. They dreamed of food or breaking their diet. They were anxious and depressed; some were suicidal. They hid food in their rooms. Researchers warn that it is possible that weight reduction doesn"t result in normal weight, but in an abnormal state resembling that of starved non-obese people. Thin people, however, suffer from the opposite: they have to make a great effort to gain weight. Ethan Sims, of the University of Vermont, got prisoners to volunteer to gain weight. In four to six months, they ate as much as they could. They succeeded in increasing their weight by 20 to 25 percent. But months after the study ended, they were back to normal weight and stayed there. This does not mean that people are completely without hope in controlling their weight. It means that those who tend to be fat will have to constantly battle their genetic inheritance if they want to significantly lower their weight. The findings also provide evidence for something scientists thought was true—each person has a comfortable weight range. The range might be as much as 9kg. Someone might weigh 60～69kg without too much effort. But going above or below the natural weight range is difficult. The body resists by feeling hungry or full and changing the metabolism to push the weight back to the range it seeks.

单选题In 1816 it seemed inevitable that Southern states would break away from the Union.______

单选题The rules are too （rigid） to allow for humane error.

单选题The most (crucial) problem any economic system faces is how to use its scarce resources.

单选题Listening to Birdsong A male zebra finch (雀科鸣鸟) chirps (鸣) away to himself. Suddenly he notices a female bird nearby. He realizes he has an audience and immediately changes his song. Can the female tell the difference in his performance? According to a new study, the female zebra finch knows. And she prefers the special trills he creates when he sings to her. A male zebra finch changes his song when singing to a female in ways that people can barely detect. But the female finch can tell the difference. Scientists had noticed slight variations in the songs of male zebra finches based on whether they were singing alone or whether there was a female (and potential mate) nearby. With an audience, the males sped up the pace of their songs and controlled the notes they used. For this study, researchers Sarah C. Woolley and Allison Doupe, at the University of California, San Francisco, decided to focus attention on the listening females, which have not been well studied in the past. In the study, Woolley and Doupe set up a long cage with a sound speaker at each end. One broadcast the sound of a male zebra finch singing to himself, like someone singing in the shower. The other speaker broadcast a male performing for a female audience, as if he was giving a concert. Female birds were placed between the two speakers. Some of the birds had mates, others didn"t. The females shifted around a bit, and then most of them hopped over to sit beside just one speaker. All the birds that made a clear choice liked songs meant for a female audience, even if they"d never met the male. Mated females also had a chance to listen to two different performance songs, one from an unknown male, and one from their mate. They spent more time listening to the concert version of their mates" songs, this suggests that after a while, females learn to recognize and prefer the songs of their mates. Scientists then studied the brains of the females. They found certain areas of the brain perked up (活跃起来) when the birds listened to the concert songs. These brain areas may be involved in recognizing and evaluating the songs, and storing the memories of them. This research deals with what"s called directed communication, when the communicator, or sender, focuses the message for a specific audience. One example is the way morns speak to their babies. Mothers around the world use the same sort of high-pitched sing-song chatter (喋喋不休), and the babies respond best to those sounds. Songbirds are one of the only other species known to learn their communication, in this case their songs.

单选题Thirst for Oil Worldwide every day, we devour the energy equivalent of about 200 million barrels of Oil. Most of the energy on Earth comes from the Sun. In fact enough energy from the Sun hits the planet"s surface each minute to cover our needs for an entire year, we just need to find an efficient way to use it. So far the energy in oil has been cheaper and easier to get at. But as supplies dwindle, this will change, and we will need to cure our addiction to oil. Burning wood satisfied most energy needs until the steam-driven industrial revolution, when energy-dense coal became the fuel of choice. Coal is still used, mostly in power stations, to cover orle quarter of our energy needs, but its use has been declining since we started pumping up oil. Coal is the least efficient, unhealthiest and most environmentally damaging fossil fuel, but could make a comeback, as supplies are still plentiful; its reserves are five times larger than oil"s. Today petroleum, a mineral oil obtained from below the surface of the Earth and used to produce petrol, diesel oil and various other chemical substances, provides around 40% of the world"s energy needs, mostly fuelling automobiles. The US consumes a quarter of all oil, and generates a similar proportion of greenhouse gas emissions. The majority of oil Comes from the Middle East, which has half of known reserves. But other significant sources include Russia, North America, Norway, Venezuela and the North Sea. Alaska"s Arctic National Wildlife Refugel could be a major new US source, to reduce reliance on foreign imports. Most experts predict we will exhaust easily accessible reserves within 50 years, though opinions and estimates vary. We could fast reach an energy crisis in the next few decades, when demand exceeds supply. As conventional reserves become more difficult to access, others such as oil shares and tar sands may be used instead. Petrol could also be obtained from coal. Since we started using fossil fuels, we have released 400 billion tonnes of carbon, and burning the entire reserves could eventually raise world temperatures by 13℃. Among other horrors, this would result in the destruction of all rainforests and tile inching of all Arctic ice.

单选题A notably short man, he plays basketball with his staff several times a week.