单选题Losing Weight Girls as young as 10 years old are dieting and in danger of developing unhealthy attitudes about weight, body image and food, a group of Toronto researchers reported Tuesday. Their study of 2,279 girls aged 10 to 14 showed that while the vast majority had healthy weights, nearly a third felt they were overweight and were trying to lose pounds. Even at the tender age of 10, nearly 32 per cent of girls felt "too fat" and 31 per cent said they were trying to diet. McVey, a researcher at the Hospital for Sick Children in Toronto, and her colleagues analyzed data collected in a number of surveys of southern Ontario school girls between 1993 and 2003, reporting their findings in Tuesday"s issue of the Canadian Medical Association Journal. Nearly 80 percent of the girls had a healthy body weight and only 7.2 per cent were considered overweight using standard weight-to-height ratios. Most researchers suggest the rate of overweight children in this country is several times higher than that figure. Nearly 30 percent of the girls reported they were currently trying to lose weight, though few admitted to dangerous behavior such as self-induced vomiting. Still, a test that measured attitudes towards eating showed 10.5 per cent of survey participants were already at risk of developing an eating disorder. "We"re not talking about kids who"ve been prescribed a diet because they"re above average weight or overweight. We"re talking about children who are within a healthy weight range. And they have taken it upon themselves to diet to lose weight," McVey said, acknowledging she found the rates disturbing. She said striking a balance between healthy weights and healthy attitudes towards food and body image is a complex task, with no easy solutions.

单选题His claims seem credible to many people.

单选题The sports meet was postponed owing to the heavy rain.

单选题Living with Computer After too long on the Net, even a phone call can be a shock. My boyfriend's Liverpudlian accent suddenly becomes hard to understand after the clarity of his words on screen; a secretary's tone seems more rejecting than I'd imagined it would be. Time itself becomes fluid—hours become minutes, and alternately seconds stretch into days. Weekends, once a highlight of my week, are now just two ordinary days. For the last three years, since I stopped working as a producer for Charlie Rose, I have done much of my work as a tele-commuter (远程交谈者). I submit articles and edit them via E-mail and communicate with colleagues on Internet mailing lists. My boyfriend lives in England, so much of our relationship is computer-mediated. If I desired, I could stay inside for weeks without wanting anything. I can order food, and manage my money, love and work. In fact, at times I have spent as long as three weeks alone at home, going out only to get mail and buy newspapers and groceries. I watched most of the blizzard (风) of '96 on TV. But after a while, life itself begins to feel unreal. I start to feel as though I've merged with my machines, taking data in, spitting them back out, just another node (节点) on the Net. Others on line report the same symptoms. We start to strongly dislike the outside forms of socializing. It's like attending an A.A. meeting in a bar with everyone holding a half-sipped drink. We have become the Net opponents' worst nightmare. What first seemed like a luxury, crawling from bed to computer, not worrying about hair, and clothes and face, has become an avoidance, a lack of discipline. And once you start replacing real human contact with cyber-interaction (网上交流), coming back out of the cave can be quite difficult. At times, I turn on the television and just leave it to chatter in the background, something that I'd never done previously. The voices of the programs soothe (安危) me, but then I'm jarred (使感不快) by the commercials. I find myself sucked in by soap operas, or compulsively (强制性地) needing to keep up with the latest news and the weather. "Dateline," "Frontline," "Nightline," CNN, every possible angle of every story over and over and over, even when they are of no possible use to me. Work moves from foreground to background.

单选题Which of the following is NOT true of Britain?

单选题At what temperature does the superconducting ceramic lose its resistance?

单选题The Cold Places The Arctic is a polar region. It surrounds the North Pole. Like Antarctica, the Arctic is a land of ice and snow. Antarctica holds the record for a low temperature reading—125 degrees Fahrenheit below zero. Reading of 85 degrees below zero is common in both the Arctic and Antarctica. Winter temperatures average 30 degrees below zero in the Arctic. At the South Pole the winter average is about 73 degrees below zero. One thing alone makes it almost impossible for men to live in Antarctica and in parts of the Arctic. This one thing is the low temperature-the killing chill of far North and the polar South. To survive, men must wear the warmest possible clothing. They must build windproof shelters. They must keep heaters going at all times. Not even for a moment can they be unprotected against the below-zero temperatures. Men have a way of providing for themselves. Polar explorers wrap themselves in warm coats and furs. The cold makes life difficult. But the explorers can stay alive. What about animals? Can they survive? Do we find plants? Do we find life in the Arctic and in Antarctica? Yes, we do. There is life in the oceans. There is life on land. Antarctica, as we have seen, is a cold place indeed. But this has not always been the case. Expedition scientists have discovered that Antarctica has not always been a frozen continent. At one time the weather in Antarctica may have much like our own. Explorers have discovered coal in Antarctica. This leads them to believe that Antarctica at one time was a land of swamps and forests. Heat and moisture must have kept the trees in the forests alive.

单选题A crowd {{U}}gathered{{/U}} to see what had happened. A.collected B.fixed C.divided D.assist

单选题The mathematical model recommended by Britain's National Radiological Protection Board (NRPB) predicted that the screening programme would cause 36 cancers per 100,000 women, 18 of them fatal. The model preferred by the UN Scientific Committee on the Effects of Atomic Radiation led to a lower figure of 20 cancers. The researchers argue that the level of radiation-induced cancers is "not very significant" compared to the far larger number of cancers that are discovered and treated. The Valencia programme, they say, detects between 300 and 450 cases of breast cancer in every 100,000 women screened. The model recommended by the UN Scientific Committee on the Effects of Atomic Radiation would probably cause ______ cancers in 100,000 women screened.A. 300B. 450C. 36D. 20

单选题A3XX will be bigger than the B-2 stealth bomber.

单选题{{B}}第三篇{{/B}} Defending the Theory of Evolution Still Seems Needed Judith S. Weis, a biology professor who serves as president of the American Institute of Biological Sciences (AIBS) is leading a nationwide effort to "defend" the theory of evolution. Weis leads the effort in the face of what the institute views as opposition and indifference from school boards and government entities. The Institute believes that the teaching of evolution in America is being diminished by the teaching of creationism as well as by an overall lack of teaching Darwin's theory in high school. "There's nothing that requires schools to teach evolution. Sometimes teachers in high schools just leave it out. However from the point of view of biologists, evolution is the central theory of biology upon which everything is based," said Weis. "Unfortunately, teaching evolution has become a political issue in many parts of the country and AIBS, as a representative of biologists, wanted to be a major force speaking out in favor of its teaching. " Weis said the institute is working together with the American Geological Institute and the National Association of Biology Teachers and its 80-plus member organizations to address" the political and legislative threats to teaching evolution. In states challenging its teaching, the institute responds by sending letters to school boards and state legislatures, by providing testimony at public meetings and by notifying members and affiliated organizations. AIBS, with more than 80 member societies and 250,000 members, has established an email system enabling scientists and teachers in each state, and member societies, to keep each other informed about threats to the teaching of evolution. Darwin's theory of evolution holds that living things change and adapt to their environment and that present-day species ( including human beings) are descended from earlier species through modification by natural selection. The theory has been accepted by scientists for nearly 100 years, Weis said, and has been refined, extended and strengthened over the years by findings in paleontology and developmental biology. Discoveries in genetics, molecular biology and genomics—all of which provide significant benefits for human health—would not be possible without the underlying knowledge of evolution. And, Weis adds, "modem molecular biology and genomics have increased our understanding of how evolution works." Nonetheless, evolution remains a politically, if not scientifically, controversial issue. Weis said that this year alone, seven states have had either local or statewide efforts to water down the teaching of evolution, or "balance" it with the teaching of creationism—a religious belief that different species were created separately by a higher power, such as God. "Rarely does anyone now use the word ' creationism, ' because that's too obvious," Weis said. "The current terminology is ' intelligent design. ' "

单选题Global Warming At the Kyoto conference on global warming in December 1997, it became abundantly clear how complex it has become to work out international agreements relating to the environment because of economic concerns unique to each country. It is no longer enough to try to forbid certain activities or to reduce emissions of certain substances. The global challenges of the interlink between the environment and development increasingly bring us to the core of the economic life of states. During the late 1980s we were able, through international agreements, to make deep cuts in emissions harmful to the ozone layer. These reductions were made possible because substitutions had been found for many of the harmful chemicals and, more important, because the harmful substances could be replaced without negative effects on employment and the economies of states. Although the threat of global warming has been known to the world for decades and all countries and leaders agree that we need to deal with the problem, we also know that the effects of measures, especially harsh measures taken in some countries, would be nullified (抵消) if others countries do not control their emissions. Whereas the UN team on climate change has found that the emissions of carbon dioxide would have to be cut globally by 60% to stabilize the content of CO 2 in the atmosphere, this path is not feasible for several reasons. Such deep cuts would cause a breakdown of the world economy. Important and populous (人口众多的) low or medium income countries are not yet willing to under-take legal commitments about their energy uses. In addition, the state of world technology would not yet permit us to make such a big leap. We must, however, find a solution to the threat of global warming early in the 21st century. Such a commitment would require a degree of shared vision and common responsibilities new to humanity. Success lies in the force of imaginations, in imagining what would happen if we fail to act. Although many living in cold regions would welcome the global warming effect of a warmer summer, few would cheer the arrival of the subsequent diseases, especially where there had been none.

单选题Your dog needs at least 20 minutes of vigorous exercise every day. A. energetic B. physical C. regular D. free

单选题{{B}}第二篇{{/B}} {{B}}Electric Backpack{{/B}} Backpacks are convenient. They can hold your books, your lunch, and a change of clothes, leaving your hands free to do other things. Someday, if you don't mind carrying a heavy load, your backpacks might also power your MF3 player, keep your cell phone running, and maybe even light your way home. Lawrence C. Rome and his colleagues from the University of Pennsylvania in Philadelphia and the Marine Biological Laboratory in Woods Hole, Mass., have invented a backpack that makes electricity from energy produced while its wearer walks. In military actions, search-and-rescue operations, and scientific field studies, people rely increasingly on cell phones, global positioning system (GPS) receivers, night-vision goggles, and other battery-powered devices to get around and do their work. The backpack's electricity-generating feature could dramatically reduce the amount of a wearer's load now devoted to spare batteries, report Rome and his colleagues in the Sept. 9 Science. The backpack's electricity-creating powers depend on springs used to hang a cloth pack from its metal frame. The frame sits against the wearer's back, and the whole pack moves up and down as the person walks. A gear mechanism converts vertical movements of the pack to rotary motions of an electrical generator, producing up to 7.4 watts. Unexpectedly, tests showed that wearers of the new backpack alter their gaits in response to the pack's oscillations, so that they carry loads more comfortably and with less effort than they do ordinary backpacks. Because of that surprising advantage, Rome plans to commercialize both electric and non-electric versions of the backpack. The backpack could be especially useful for soldiers, scientists, mountaineers, and emergency workers who typically carry heavy backpacks. For the rest of us, power-generating backpacks could make it possible to walk, play video games, watch TV, and listen to music, all at the same lime. Electricity-generating packs aren't on the market yet, but if you do get one eventually, just make sure to look both ways before crossing the street!

单选题We must harness the skill and creativity of our workforce.

单选题Halloween Halloween is an autumn holiday that Americans celebrate every year. It means "holy evening", and it comes every October 31, the evening before All-Saints Day. It used to be thought the most wonderful night of the year. It was the night when witches and evil spirits came back on earth. People kept up many strange old customs in an effort to keep these evil things away. Farmers used to light big fires in their fields, and the farm workers and their families would walk around the fields singing old songs. Sometimes they would stop to hear the local priest offer prayers to the good spirits, and ask them to help keep the evil ones away. Great care was taken that none of the farm animals were left in the fields. They would all be locked up safely in their stables, and over each of the stable doors a few rowan leaves would be hung. Witches and evil spirits would not go anywhere near the rowan tree. In more recent times, Halloween has become a time for the parties, when children dress up as witches and play all kinds of special games. After the games there is often a big supper with plenty of pumpkin pie, cakes and a lot of other delicious things to eat. But for the most part the children enjoy the fun of dressing up and playing their favorite game of "Trick or Treat". They run down each street knocking on the doors crying loudly "Trick or Treat! Money or eat!", and most people have some sweets or money ready to give them. Those that do not can expect maybe to have a tyre flattened, or their windows covered in soap. Or the children may just knock on the door and run away. Some children think of other people on Halloween. They carry boxes for UNICEF (The United Nations International Children's Emergency Fund). They ask for money to help poor children all around the world. Of course, every time they help UNICEF, they usually receive a treat for themselves, too. Every autumn, when the vegetables are ready to eat, children pick large orange pumpkins. Then they cut faces in the pumpkins and put lights inside. It looks like there is a person looking out of the pumpkin! These lights are called jack-o'-lanterns, which means "Jack of the lantern". But in this modern age many of the pumpkins are being replaced with plastic electric ones that can be brought out each year.

单选题Needlepoint has always been an elegant and {{U}}costly{{/U}} form of embroidery.

单选题Five minutes left, the {{U}}outcome{{/U}} of the match was still in doubt. A. result B. judgment C. decision D. event

单选题Blackmarket for Gun in the US As Americans digest the news of another gun atrocity, a mall shooting in Nebraska on December 5th, they cannot be blamed for thinking that guns are in too ready supply. But an article in the latest Economic Journal suggests that the demand for illegal guns, at least, is not met as easily as people might fear. Sudhir Venkatesh, now of Columbia University, has talked to 132 gang-members, 77 prostitutes, 116 gun-owning youths, 23 gun-dealers and numerous other denizens of Chicago"s Grand Boulevard and Washington Park neighbourhoods. He did not find many satisfied customers. Chicago has unusually tough restrictions on legal handguns. Even so the black market is surprisingly "thin", attracting relatively few buyers and sellers. The authors reckon that the 48,000 residents of the two neighbourhoods buy perhaps 1,400 guns a year, compared with at least 200,000 cocaine purchases. Underground brokers sell guns for $ 150～350, a mark-up of perhaps 200% over the legal price. They also demand a fee of $30～50 for orchestrating the deal. Even then, 30～40% of the transactions fall through because the seller cannot secure a gun, gets cold feet or cannot agree on a location for the deal. Buyers also find it hard to verify the quality of the merchandise. They often know little about the weapons they covet. "Tony", who owns a 38 calibre handgun, learnt how to use his weapon by fiddling with it. He even put a stone in it. "Did it fire?" Mr Venkatesh asked. "I"m not sure. I think it did," Tony said. Fortunately for Tony and his peers, their rivals and the victims of crime cannot tell if their guns work any better than they can. Often, showing the "bulge" is enough to gain the respect of rival gangs. In robberies brandishing the weapon will usually do. Storekeepers do not wait for proof that it works. Markets can overcome thinness, the paper says; they can also overcome illegality. But they cannot overcome both. A thin market must rely on advertising or a centralised exchange: eBay, for example, has dedicated pages matching sellers of imitation pearl pins or Annette Funicello bears to the few, scattered buyers that can be found. But such solutions are too cumbersome and conspicuous for an underground market. The drugs market, by contrast, slips through the law"s fingers because of the natural density of drug transactions. Dealers can always find customers on their doorstep, and buyers can reassure themselves about suppliers through repeated custom. There are no fixed and formal institutions that the police could easily throttle. Indeed, the authors argue that the gun market may be threadbare partly because the drug market is so plump. Gang-leaders are wary of gun-dealing because the extra police scrutiny that guns attract would jeopardise their earnings from coke and dope. Even Chicago"s gang-leaders have to worry about the effect of crime on commerce.