单选题Smoking will be banned in all public places here. A．forbidden B．allowed C．permitted D．promoted

单选题The city has decided to w Udo away with/U all the old buildings in its center.

单选题Walk a Quarter-Mile or Die If you can walk a quarter-mile, odds (可能性) are you have at least six years of life left in you, scientists say. And the faster you can (1) it, the longer you might live. While walking is no guarantee of (2) or longevity (长寿), a new study found that the ability of elderly people to do the quarter-mile was an "important determinant (决定因素)" in whether or not they'd be (3) six years later and how much illness and disability they would endure. "The (4) to complete this walk was a powerful predictor of health outcomes," said study leader Anne Newman of the University of Pittsburgh School of Medicine. "In fact, we (5) that the people who could not complete the walk were (6) an extremely high risk of later disability and death. " Newman and colleagues recruited nearly 2,700 white and African-American men and women aged 70 to 79 to (7) the walk. All the participants were screened and determined to be in relatively (8) health, and they had all said they had previously walked that far with no (9) . Only 86 percent of them finished, (10) . The scientists then monitored the health and mortality of all (11) for the next six years. "There was a big gap in health outcomes (12) people who could complete the longer walk and people who could not, with the latter being at an extremely high (13) of becoming disabled or dying," Newman said. "What was really surprising is that these people were not (14) of how weak they actually were. " Finishing times were found to be crucial, too. Those who completed the walk but were among the slowest 25 percent (15) three times greater risk of death than the speedier folks.

单选题When he was the director of the company, his first Uaccomplishment/U was to improve the working conditions.

单选题Robots May Allow Surgery in Space Small robots designed by University of Nebraska researchers may allow doctors on Earth to help perform surgery on patients in space. The tiny, wheeled robots, 31 are about 3 inches tall and as wide as a lipstick case, can be slipped into small incisions (切口) and computer-controlled by surgeons in different locations. Some robots are 32 with cameras and lights and can send images back to surgeons and others have surgical 33 attached that can be controlled remotely. "We think this is going to 34 open surgery," Dr. Dmitry Oleynikov said at a news conference. Oleynikov is a specialist 35 computer-assisted surgery at the University of Nebraska Medical Center in Omaha. Officials hope that NASA will teach 36 to use the robots soon enough so that surgeries could one day be performed in space. On earth, the surgeons could 37 the robots themselves from other locations. For example, the robots could 38 surgeons in other places to work on injured soldiers on the front line. Researchers plan to seek federal regulatory (联邦管理局的) 39 early next year. Tests on animals have been successful, and tests on humans in England will begin very soon. The camera-carrying robots can provide 40 of affected areas and the ones with surgical tools will be able to maneuver (操控) inside the body in ways surgeons" hands can"t. The views from the camera-carrying robots are better than the naked eye, because they send back color images that are magnified (放大). Because several robots can be 41 through one incision, they could reduce the 42 and size of cuts needed for surgery, which would 43 recovery time. This is particularly helpful to those patients who have been debilitated (使虚弱) by long illness. Eventually, Oleynikov said, the tiny robots may enable surgeons to 44 without ever placing their hands in patients" bodies. "That"s the goal;" Oleynikov said. "It"s getting easier and easier. We can do even more with these 45 "

单选题The agreement was terminated immediately.

单选题阅读下面的短文，文中有15处空白，每处空白给出了4个选项，请根据短文的内容从4个选项中选择1个最佳答案。 {{B}}Standard English{{/B}} Standard English is the variety of English which is usually used in print and which is normally taught in schools and to non-native speakers leaning the language. It is also the variety which is normally spoken by educated people and used in news broadcasts and other{{U}} (51) {{/U}}situations. The difference between standard and nonstandard, it should be noted, has{{U}} (52) {{/U}}in principle to do with differences between formal and colloquial{{U}} (53) {{/U}}; standard English has colloquial as well as formal variants. Historically, the standard variety of English is based on the London{{U}} (54) {{/U}}of English that developed after the Norman Conquest resulted in the removal of the Court from Winchester to London. This dialect became the one{{U}} (55) {{/U}}by the. educated, and it was developed and promoted{{U}} (56) {{/U}}a model, or norm, for wider and wider segments of society. It was also the{{U}} (57) {{/U}}that was carried overseas, but not one unaffected by such export. Today, standard English is arranged to the extent that the grammar and vocabulary of English are{{U}} (58) {{/U}}the same everywhere in the world where English is used;{{U}} (59) {{/U}}among local standards is really quite minor,{{U}} (60) {{/U}}the Singapore, South Africa, and Irish varieties are really very{{U}} (61) {{/U}}different from one another so far as grammar and vocabulary are concerned. Indeed, Standard English is so powerful that it exerts a tremendous{{U}} (62) {{/U}}on all local varieties, to the extent that many of long-established dialects of England have{{U}} (63) {{/U}}much of their vigor (活力) and there is considerable pressure on them to be{{U}} (66) {{/U}}. This latter situation is not unique{{U}} (65) {{/U}}English: it is also true in other countries where processes of standardization are underway. But it sometimes creates problems for speakers who try to strike some kind of compromise between local norms and national, even supranational (跨国的) ones.

单选题Since 1992, cancer death rates among black Americans

单选题 阅读下面的短文，文中有15处空白，每处空白给出了4个选项，请根据短文的内容从 4个选项中选择1个最佳答案。 {{B}}Dark Forces Dominate Universe{{/B}} The earth, moon, sun and all visible stars in the sky make up less than one percent of the universe. Almost all the rest is dark matter and dark energy, unknown forces that {{U}}(51) {{/U}}astronomers. Observations in recent years have changed the basic{{U}} (52) {{/U}}of how the universe evolved and have indicated how little is known about the major forces and substances that{{U}} (53) {{/U}}our world. Astronomers now know that luminous (发光的) matter -- stars, planets and hot gas -- accounts{{U}} (54) {{/U}}only about 0.4 percent of the universe. Non-luminous components, such as black holes and intergalactic (星系间的) gas,{{U}} (55) {{/U}}up 3.6 percent. The rest is either dark matter, about 23 percent, or dark energy, about 73 percent. Dark matter, sometimes{{U}} (56) {{/U}}"cold dark matter," has been known for some time. Only recently have researchers come to understand the key role it {{U}}(57) {{/U}}in the formation of stars, planets and even people. "We{{U}} (58) {{/U}}our very existence to dark matter," said physicist Paul Steinhardt and a co-author of a review on dark matter which{{U}} (59) {{/U}}not long ago in the journal Science. "Dark matter dominated the structure{{U}} (68) {{/U}}in the early universe," Steinhardt said. "For the first few billion years dark matter contained most of the mass of the universe. You can think of ordinary matter{{U}} (61) {{/U}}a froth (泡沫) of an ocean of dark matter. The dark matter clumps (结成块) and the ordinary matter falls into it. That {{U}}(62) {{/U}}to the formation of the stars and galaxies (星系)." Without dark matter, "there would be virtually no structures in the universe." The nature of dark matter is{{U}} (63) {{/U}}. It cannot be seen or detected directly. Astronomers know it is there because of its{{U}} (64) {{/U}}on celestial (天体的) objects that can be seen and measured. But the most dominating force of all in the universe is called dark energy, a recently {{U}}(65) {{/U}}power that astronomers say is causing the galaxies in the universe to separate at a faster and faster speed.

单选题The advantage of the new handgrip is that

单选题" The utilities are more interested in protecting their stranglehold on the power grid and preserving their century-old business model than they are producing clean electricity," says Jim Harvey, who heads up the Joshua Tree, Calif. — based Alliance for Responsible Energy Policy, an advocacy group that's staunchly opposed to utility-generated solar power. Harvey actually believes that the country's entire renewable portfolio can be achieved through rooftop solar alone. That may be possible from a sheer megawatts perspective, but from a practical standpoint, it's way over— ambitious. With no centralized source, how do you run traffic or street lights? What if it rains for a week? We still don't have foolproof means to store solar power, so for how, distributed generation needs the grid as a backup. What does the author think of Harvey's idea of achieving the country's entire renewable portfolio through rooftop solar alone?A. It is possible.B. It is not practical.C. It is out of question.D. It takes time to se

单选题The last few weeks have been enjoyable. A. close B. near C. past D. several

单选题Marvelous Metamaterials Invisibility cloaks would have remained impossible, forever locked in science fiction, had it not been for the development of metamaterials. In Greek, "meta" means beyond, and metamaterials can do things beyond what we see in the natural world—like shuffle light waves around an object, and then bring them back together. If scientists ever man-age to build a full-fledged invisibility cloak, it will probably be made of metamaterials. "We are creating materials that don"t exist in nature, and that have a physical phenomenon that doesn"t exist in nature," says engineer Dentcho Genov. "That is the most exciting thing." Genov designs and builds metamaterials—such as those used in cloaking, at Louisiana Tech University in Ruston, Louisiana. An invisibility cloak will probably not be the first major accomplishment to come from the field of metamaterials. Other applications are just as exciting. In many labs, for example, scientists are working on building a hyperlens. A lens is a device, usually made of glass, that can change the direction of light waves. Lenses are used in microscopes and cameras to focus light, thus allowing a researcher to see small things or a photographer to capture image of things that are far away. A hyperlens, however, would be made of metamaterials. And since metamaterials can do things with light that ordinary materials can"t, the hyperlens would be a powerful tool. A hyperlens would allow researchers to see things at the smallest scale imaginable as small as the wavelength of visible light. Genov points out that the science of metamaterials is driven by the imagination. If someone can think of an idea for a new behavior for light, then the engineers can find a way to design a device using metamaterials. "We need people who can imagine," he says. Since 2006, many laboratories have been exploring other kinds of metamaterials that don"t involve just visible light. In fact, scientists are finding that almost any kind of wave may respond to metamaterials. At the Polytechnic University of Valencia in Spain, Jose Sanchez-Dehesa is working with acoustics, or the science of sound. Just as an invisibility cloak shuffles waves of light, an "acoustic" cloak would shuffle waves of sound in a way that"s not found in nature. In an orchestra hall, for example, an acoustic cloak could redirect the sound waves-so someone sitting behind a column would hear the same concert as the rest of the audience, without distortion. Sanchez-Dehesa, an engineer, recently showed that it"s possible to build such an acoustic cloak, though he doubts we"ll see one any time soon. "In principle, it is possible," he says, but it might be impossible to make one, he adds. Other scientists are looking into ways to use larger metamaterials as shields around islands or oil rigs as protection from tsunamis. A tsunami is a giant, destructive wave. The metamaterial would redirect the tsunami around the rig or island, and the wave would resume its journey on the other side without causing any harm.

单选题{{B}}第二篇{{/B}} {{B}}How to Forgive{{/B}} To forgive may be divine, but no one ever said it was easy. When someone has deeply hurt you, it can be extremely difficult to let go of your {{U}}grudge.{{/U}} But forgiveness is possible—and it can be surprisingly beneficial to your physical and mental health. “People who forgive show less depression, anger and stress and more hopefulness,” says Frederic Luskin, Ph. D., author of Forgive for Good (Harper Collins, 2002). “So it can help save on the wear and tear on our organs, reduce the wearing out of the immune system and allow people to feel more vital.” So how do you start the healing? Try following these steps: Calm yourself. To defuse your anger, try a simple stress-management technique. “Take a couple of breaths and think of something that gives you pleasure: a beautiful scene in nature, someone you love,” Luskin says. Don’t wait for an apology. “Many times the person who hurt you has no intention of apologizing,” Luskin says. “They may have wanted to hurt you or they just don’t see things the same way. So if you wait for people to apologize, you could be waiting an awfully long time.” Keep in mind that forgiveness does not necessarily mean reconciliation with the person who upset you or condoning of his or her action. Take the control away from your offender. Mentally replaying your hurt gives power to the person who caused you pain. “Instead of focusing on your wounded feelings, learn to look for the love, beauty and kindness around you,” Luskin says. Try to see things from the other person’s perspective. If you empathize with that person, you may realize that he or she was acting out of ignorance, fear—even love. To gain perspective, you may want to write a letter to yourself from your offender’s point of view. Recognize the benefits of forgiveness. Research has shown that people who forgive report more energy, better appetite and better sleep patterns. Don’t forget to forgive yourself. “For people, forgiving themselves is the biggest challenge,” Luskin says. “But it can rob you of your self-confidence if you don’t.”

单选题No fasteners will be used in building A3XX because all components will be welded together.

单选题The telephone system is no longer {{U}}operative{{/U}}. A. flowing B. moving C. rotating D. working

单选题The first question is how hest to separate clean element—glass containers, plastics, and some paper and metal containers that is relatively clean when discarded-from mixed refuse (废料, 垃圾). This clean element is the main target for Britain's recyclers. The method of collection is important because manufacturers will not reuse collected material unless it is clean and available in sufficient quantities. A bewildering assortment(混合) of different collection schemes operates in the rest of Europe, and pilot schemes are now under way in many British cities. Recycling is possible only whenA. it is monitored by the government.B. different collection schemes operate.C. there is enough clean material.D. there is a small amount of clean material.

单选题Denny His nickname is Denny". He weighs 400 pounds; he is fearless and he never goes to sleep on the job. An ideal security guard? For many situations he may be. And if he"s so good that you wish you had a dozen like him, just place your order. Denny is a robot guard. Denny can detect, within a 150-thor radius, the presence of anything or anybody that shouldn"t be there. Its swiveling (旋转) head contains microwave and infrared sensors that can detect people as well as smoke. In future editions the head will also contain sensors that can smell the weak smell of a human body. A high-resolution TV camera in Denny"s head is on at all time. When something unexpected comes into view, the TV transmitter switches on. Thus the human overseer (看管人) in the control center sees the sudden appearance of a picture on the monitor screen. At the same time the picture is automatically videotaped. Normal speed of the robot guards is about one mile an hour, and they can even talk: "you have been detected," warns the voice from the clever guard. Denny is designed to patrol corridors and other areas after lock-down hours (of course, he can work round the clock when necessary), not to move among people. If, say, a prisoner does get near the corridor where he should not be, it"ll immediately tell its base station by radio. Denny has understandable limitations. He can"t open doors or watch stairs, for example, or distinguish a friend from an enemy. Thus he will have to go about unarmed. And he won"t be able to replace human security guards where people move about freely.

单选题It is not possible for people to {{U}}remember{{/U}} everthing that they have thought.

单选题{{B}}第三篇{{/B}} Egypt Felled by Famine Even ancient Egypts mighty pyramid builders were powerless in the face of the famine that helped bring down their civilian around 2180 BC. Now evidence gleaned(搜集) from mud deposited by the River Nile suggests that a shift in climate thousands of kilometers to the south was ultimately to blem -- and the same or worse could happen today. The ancient Egyptians depended on the Niles annual floods to irrigate their crops. But any change in climate that pushed the African monsoons(季风)southwards out of Ethiopia would have diminished these floods. Dwindling(逐渐变少；使变少)rains in the Ethiopian highlands would have meant fewer plants to establish the soil. When rain did fall it would have washed large amounts of soil into the Blue Nile and into Egypt, along with sediment(沉积；沉积物)from the White Nile. The Blue Nile mud has a different isotope signature(签名；特征) from that of the White Nile. So by analyzing isotope(同位素；核素)differences in mud deposited in the Nile Delta, Michael Krom of Leeds University worked out what proportion of sediment came from each branch of the river. Krom reasons that during periods of drought, the amount of the Blue Nile mud in the river would be relatively high. He found that one of these periods, from 4,500 to 4,200 years ago, immediately predates the fall of the Egypts Old Kingdom. The weakened waters would have been catastrophic for the Egyptians. Changes that affect food supply dont have to be very large to have a ripple effect in societies, says Bill Ryan of the Lamont Doherty Earth Observatory(天文台)in New York. "Similar events today could be even more devastating, " says team member Daniel Stanley, a geoarchaeologist(地质考古学家) from the Smithsonian Institution in Washington, D. C. "Anything humans do to shift the climate belts would have an even worse effect along the Nile system because the populations have increased dramatically. "