单选题The telephone system is no longer operative .

单选题Longer Lives for Wild Elephants Most people think of zoos as safe places for animals, where struggles such as difficulty finding food and avoiding predators don't exist. Without such problems, animals in zoos should live to a ripe old age. But matter may not be true for the largest land animals on Earth. Scientists have known that elephants in zoos often suffer from poor health. They develop diseases, joint problems and behavior changes. Sometimes, they even become infertile or unable to have babies. To learn more about how captivity affects elephants, a team of international scientists compared the life spans of female elephants born in zoos with female elephants living outdoors in their native lands. Zoos keep detailed records of all the animals in their care, documenting factors such as birth dates, illnesses, weight and death. These records made it possible for the researchers to analyze 40 years of data on 800 African and Asian elephants in zoos across Europe. The scientists compared the life spans of the zoo born elephants with the life spans of thousands of female wild elephants in Africa and Asian elephants that work in logging camps, over approximately the same time period. The team found that female African elephants born in zoos lived an average of 16.9 years. Their wild counterparts who died of natural causes lived an average of 56 years--more than three times as long. Female Asian elephants followed a similar pattern. In zoos, they lived 18.9 years, while those in the logging camps lived 41.7 years. Scientists don't yet know why wild elephants seem to fare so much better than their zoo-raised counterparts. Georgia Mason, a biologist at the University of Guelph in Canada who led the study, thinks stress and obesity may be to blame. Zoo elephants don't get the same kind of exercise they would in the wild, and most are very fat. Elephant social lives are also much different in zoos than in the wild, where they live in large herds and family groups. Another finding from the study showed that Asian elephants born in zoos were more likely to die earlier than Asian elephants captured in the wild and brought to zoos. Mason suggests stress in the mothers in zoos might cause them to have babies that are less likely to survive. The study raises some questions about acquiring more elephants to keep in zoos. While some threatened and endangered species living in zoos reproduce successfully and maintain healthy populations, which doesn't appear to be the case with elephants." Currently, zoos alert consumers of elephants, not net producers," Mason says.

单选题Before you decide on a vocation. it might be a good idea to consult a few good friends.A. careerB. holidayC. planD. research

单选题{{B}}第二篇{{/B}} Most of the pioneers of low-temperature physics expected gases to liquefy, but none of them predicted superconductivity. This phenomenon was discovered in 1911 by Onnes while he was studying frozen mercury. More than 40 years passed before physicists were able to offer an explanation for superconductivity. The accepted theory, developed in the 1950s, holds that the fundamental behavior of electrons changes at very low temperatures because of the effects of quantum mechanics. Electrons are tiny particles that make up the outer part of an atom, circling rapidly around the nucleus of the atom. In a regular conductor—a metal that conducts an electric current—the outermost electrons are not bound tightly to the atoms, and so they move around relatively freely. The flow of these electrons is an electric current. At normal temperatures, a conductor's electrons cannot move completely freely through the metal because they are "bumped around" by the metal's atoms. But according to the leading theory of superconductivity, when a metal is very cold, electrons form pairs. Then, like couples maneuvering on a crowded dance floor but never colliding, the paired electrons are able to move unimpeded through the metal. In pairing up, it seems, the electrons are able to "blend together" and move in unison without resistance. This explanation seems to account for superconductivity at extremely low temperatures, but in 1986 scientists in Switzerland found that some metal-containing ceramics are superconductors at much higher temperatures. By 1992, scientists had developed ceramics that become superconducting at - 297'F, and some researchers speculated that room-temperature superconductors may be possible. Scientists are still trying to formulate a theory for high-temperature superconductivity. The new ceramic materials can be maintained at their superconducting temperatures, with relatively inexpensive liquid nitrogen rather than the much colder and much more costly liquid helium required by metal superconductors. The cost difference could make superconductivity practical for many new technologies. For example, magnetically levitated trains, which require superconducting electromagnets, would be much cheaper to build than they are now. Superconducting devices might also be used for advanced power transmission lines and in new types of compact, ultrafast computers. But for the time being, superconductivity is finding application mostly in scientific research and in some kinds of medical imaging devices.

单选题Moderate Earthquake Strikes England A moderate earthquake struck parts of southeast England on 28 April 2007, toppling chimneys from houses and rousing residents from their beds. Several thousand people were left without power in Kent County. One woman suffered minor head and neck injuries. "It felt as if the whole house was being slid across like a fun-fair ride," said the woman. The British Geological Survey said the 4.3-magnitude quake struck at 8:19 a.m. and was centered under the English Channel, about 8.5 miles south of Dover and near the entrance to the Channel Tunnel. Witnesses said cracks appeared in walls and chimneys collapsed across the county. Residents said the tremor had lasted for about 10 to 15 seconds. "I was lying in bed and it felt as if someone had just got up from bed next to me," said Hedrick van Eck, 27, of Canterbury about 60 miles southeast of London. "I then heard the sound of cracking, and it was getting heavier and heavier. It felt as if someone was at the end of my bed hopping up and down." There are thousands of moderate quakes on this scale around the world each year, but they are rare in Britain. The April 28 quake was the strongest in Britain since 2002 when a 4.8-magnitude quake struck the central England city of Birmingham. The country"s strongest earthquake took place in the North Sea in 1931, measuring 6.1 on the Richter scale. British Geological Survey scientist Roger Musson said the quake took place on 28 April in an area that had seen several of the biggest earthquakes ever to strike Britain, including one in 1580 that caused damage in London and was felt in France. Musson predicted that it was only a matter of time before another earthquake struck this part of England. However, people should not be scared too much by this prediction, Musson said, as the modern earthquake warning system of Britain should be able to detect a forthcoming quake and announce it several hours before it takes place. This would allow time for people to evacuate and reduce damage to the minimum.

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, (1) 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 equipped (2) cameras and lights and can send images back to surgeons and others have surgical tools attached that can be (3) remotely. "We think this is going to (4) open surgery," Dr. Dmitry Oleynikov said at a news conference. Oleynikov is a (5) in computer-assisted surgery at the University of Nebraska Medical Center in Omaha. Officials hope that NASA will teach (6) to use the robots soon enough so that surgeries could one day be performed in space. On earth, the surgeons could control the robots themselves (7) other locations. For example, the robots could enable surgeons in other places to (8) on injured soldiers on the front line. Researchers plan to seek federal regulatory (9) 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 (10) 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 (11) than the naked eye, because they (12) back color images that are magnified (放大). Because several robots can be inserted through one incision, they could reduce the amount and (13) of cuts needed for surgery, which would decrease recovery time. This is particularly (14) to those patients who have been debilitated (使虚弱) by long illness. Eventually, Oleynikov said, the tiny robots may enable surgeons to work without ever (15) their hands in patients' bodies. "That's the goal," Oleynikov said. "It's getting easier and easier. We can do even more with these devices. /

单选题Which of the following statements about Flowers and Yeo is true?

单选题For some animals, {{U}}locomotion{{/U}} is accomplished by changes in body shape.

单选题I had nothing to say regarding this matter.

单选题Egypt felled by Famine Even ancient Egypt's mighty pyramid builders were powerless in the face of the famine that helped bring down their civilization around 2180 BC. Now evidence gleaned from mud deposited by the River Nile suggests that a shift in climate thousands of kilometers to the south was ultimately to blame-and the same or worse could happen today. The ancient Egyptians depended on the Nile's annual floods to irrigate their crops. But any change in climate that pushed the African monsoons southwards out of Ethiopia would have been diminished these floods. Dwindling rains in the Ethiopian highlands would have meant fewer plants to stablise the soil. When rain did fall it would have washed large amounts of soil into the Blue Nile and into Egypt, along with sediment from the White Nile. The Blue Nile mud has a different isotope signature from that of the White Nile. So by analyzing isotope 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 4500 to 4200 years ago, immediately predates the fall of the Egypt's Old Kingdom. The weakened waters would have been catastrophic for the Egyptians. "Changes that affect food supply don't have to be very large to have a ripple effect in societies, " says Bill Ryan of the Lamont Doherty Earth Observatory in New York. Similar events today could be even more devastating, says team member Daniel Stanley, a geoarchaeologist 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 today because the populations have increased dramatically. /

单选题The organization was bold enough to face the press.

单选题下面的短文后列出了7个句子，请根据短文的内容对每个句子做出判断：如果该句提供的是正确信息，请选择A；如果该句提供的是错误信息，请选择B；如果该句的信息文中没有提及，请选择C。 {{B}}The Need to Remember{{/B}} Some people say they have no memory at all: "I just can't remember a thing!" But of course we all have a memory. Our memory tells us who we are. Our memory helps us to make use In the present of what we have learnt in the past. in fact we have different types of memory. For example, our visual memory helps us recall facts and places. 'Some people have such a strong visual memory, they can remember exactly what they have seen, for example, pages of a book, as a complete picture. Our verbal (言语的) memory helps us remember words and figures we may have heard but not seen or written: items of a shopping list, a chemical formula, dates, or a recipe. With our emotional (情感的) memory, we recall situations or places where we had strong feelings, perhaps of happiness or unhappiness. We also have special memories for smell, taste, touch and sound, and for performing physical movements. We have two ways of storing any of these memories. Our short-term memory stores items for up to thirty seconds enough to remember a telephone number while we dial. Our long-term memory, on the other hand, may store items for a lifetime. Older people in fact have a much better long-term memory than short-term. They may forget what they have done only a few hours ago, but have the clearest remembrance (记忆) of when they were very young. Psychologists tell us that we only remember a few facts about our past, and that we invent the rest. It is as though we remember only the outline of a story. We then make up the details. We often do this in the way we want to remember them, usually so that we appear as the heroes of our own past or maybe victims needing sympathy (同情).

单选题Male and Female Pilots Cause Accidents Differently Male pilots flying general aviation (private) aircraft in the United States are more likely to crash due to inattention or flawed decision-making. While female pilots are more likely to crash from mishandling the aircraft. These are the results of a study by researchers at the Johns Hopkins University Bloomberg School of Public Health. The study identifies the differences between male and female pilots in terms of circumstances of the crash and the type of pilots error involved. "Crashes of general aviation aircraft account for 85 percent of all aviation deaths in the United States. The crash rate for male pilots, as for motor vehicle drivers, exceeds that of crashes of female pilots," explains Susan P. Baker, MPH, professor of health policy and management at the Bloomberg School of Public Health. "Because pilot youth and inexperience are established contributors to aviation crashes, we focused on only mature pilots, to determine the gender differences in the reasons for the crash." The researchers extracted data for this study from a large research project on pilot aging and flight safety. The data were gathered from general aviation crashes of airplanes and heIicopters between 1983 and 1997, involving 144 female pilots and 267 male pilots aged 40-63. Female pilots were matched with male pilots in a 1:2 ratio, by age, classes of medical and pilot certificates, state or area of crash, and year of crash. Then the circumstances of the crashes and the pilot error involved were categorized and coded without knowledge of pilot gender. The researchers found that loss of control on landing or takeoff was the most common circumstance for both sexes, leading to 59 percent of female pi.lots' crashes and 36 percent of males'. Experiencing mechanical failure, running out of fuel, and land!ng the plane with the landing gear up were among the factors more likely with males, while stalling was more likely with females. The majority of the crashes — 95 percent for females and 88 percent for males — involved at least one type of pilot error. Mishandling aircraft kinetics was the most common error for both sexes, but was more common among females (accounting for 81 percent of the crashes) than males (accounting for 48 percent). Males, however, appeared more likely to be guilty of poor decision-making, risk-taking, and inattentiveness, examples of which include misjudging weather and visibility or flying an aircraft with a known defect. Females, though more likely to mishandle or lose control of the aircraft, were generally more careful than their male counterparts.

单选题Monarch without a Kingdom This November, a hundred million butterflies will drop from the sky over Mexico, like autumn leaves. But for how long? Genetically modified maize (玉米) could mean extinction for this beautiful butterfly, Rafael Ruiz reports. Although its body is about 3 cm long and it only weighs 1 gm, the Monarch butterfly manages to travel 5,000 km each year. It seems to be so fragile, but its long journeys are proof of its amazing ability to survive. This autumn, the Monarch butterfly will once more set out on its journey from the U.S. It will keep going until it reaches Mexico. It travels these huge distances to escape the cold weather in the north. In November, millions of Monarchs fall like bright, golden rain onto the forests in the mountains of central Mexico. In the silence of these mountains you can hear a strange flapping (拍动) of wings, as the Monarchs arrive at their destination. In the mountains, which reach a height of 3,000 meters, the butterflies are safe. Before reaching their journey"s end they have faced strong winds, rain and snowstorms and they do not all manage to reach their destination. When the winters are really bad, perhaps 70 per cent of them will not survive. Their long journey to Mexico is thought to be one of the most amazing events in the whole of the American continent. When they get there they will stay until the beginning of April, when their internal calendar tells them that it is time to go back. The long journey, with all its dangers, begins again. These delicate creatures now face danger of another kind—from scientific progress. In the U.S., millions of farms grow genetically modified maize which is pure poison for the butterfly. Laboratory experiments have shown that half of the butterflies which feed on the leaves of genetically modified maize die within 48 hours. Not all experts agree that this variety of maize is responsible for the threat to the Monarchs. In spite of these doubts, the European Union has refused to approve new crops of genetically modified maize until further investigations have been carried out. Greenpeace is campaigning against genetically modified products (in Spain, there are already 20,000 hectares of modified maize). The environmental organization recently published a list of 100 species of butterfly in Europe alone which are threatened with extinction.

单选题The car is tested for defects before leaving the factory.

单选题I positively believe that there' s been no mistake?A. rationallyB. reasonablyC. certainlyD. boundly

单选题More Than a Ride to School The National Education Association claims, "The school bus is a mirror of the community." They further add that, unfortunately, what appears on the exterior does not always reflect the reality of a chosen community. They are right sometimes it reflects more! Just ask Liesl Denson. Riding the school bus has been more than a ride to school for Liesl. Bruce Hardy, school bus driver for Althouse Bus Company has been Liesrs bus driver since kindergarten. Last year when Liesl"s family moved to Parkesburg, knowing her bus went by her new residence, she requested to ride the same bus. This year Liesl is a senior and will enjoy her last year riding the bus. She says, "It"s been a great ride so far! My bus driver is so cool and has always been a good friend and a good listener. Sometimes when you"re a child adults do not think that what you have to say is important. Mr. Hardy always listens to what you have to say and makes you feel important." Her friends Ashley Batista and Amanda Wolfe agree. Bruce Hardy has been making Octorara students feel special since 1975. This year he will celebrate 30 years working for Althouse Bus Company. Larry Althouse, president of the company, acknowledges Bruce Hardy"s outstanding record: "You do not come by employees like Bruce these days. He has never missed a day of work and has a perfect driving record. He was recognized in 2000 by the Pennsylvania School Bus Association for driving 350,000 accident free miles. Hardy"s reputation is made further evident through the relationships he has made with the students that ride his bus." Althouse further adds, "Althouse Bus Company was established 70 years ago and has been providing quality transportation ever since. My grandfather started the business with one bus. Althouse Bus Company is delighted to have the opportunity to bring distinctive and safe service to our local school and community and looks forward to continuing to provide quality service for many more years to come." Three generations of business is not all the company has enjoyed. Thanks to drivers like Bruce Hardy, they have been building relationships through generations. Liesl"s mother Carol also enjoys fond memories of riding Bruce Hardy"s bus to the Octorara School District.

单选题He is renowned for his skill.

单选题One of the most convenient and (51) ways to see America is by riding a Greyhound bus. This interstate bus system connects all major cities in the United States, (52) people with frequent and convenient service. The bus (53) even has an international service (54) makes connection with cities in Canada and Mexico. Its network even extends (55) some of the smaller towns and out-of-the-way communities (56) the great interior of the country. Traveling by bus may (57) longer than flying by plane, but the terminals are located in the center of most cities and there is (58) to the downtown area. These buses are comfortable and air-conditioned. They are all (59) with toilets in the rear to (60) the convenience of the passengers, but there are some very severe (61) of conduct which are strictly enforced. On all buses (62) is forbidden and the consumption of alcoholic drinks is not allowed. (63) bus travel may not be suited to everyone's (64) , it affords budget travelers the (65) to see America in comfort and safety and at a leisurely unhurried pace.

单选题Thomas Edison was awarded more patents on inventions than any other American. When he died in 1931, Americans wondered how they could best show their respect for him. One suggestion was that the nation observe a minute or two of total blackout. All electric power would be shut off in homes, streets, and factories. Perhaps this suggested plan made Americans realize fully what Edison and his inventions meant to them. Electric power was too important to the country. Shutting it off for even a short time would have led to complete confusion. A blackout was out of the question. On the day of Edison's funeral, many people silently dimmed their lights. In this way they honored the man who had done more than anyone else to put the great force of electricity at his countrymen's fingertips. In order to honor Edison, many Americans dimmed their lightsA. all the year of 1931.B. on the day of Edison's funeral.C. a few days around Edison's funeral.D. for one or two minutes.