单选题The osprey flies above the water and when it spots a fish it swoops down to catch it.

单选题Their parents once lived under very severe conditions.

单选题 A Desert Between Paul and Clara Paul had long promised to marry Clara. But at thirty-three he met and married Alice. Clara was driven mad. Paul was taken to court. The judge ordered him to pay Clara $600 because of the broken promise. Paul had to borrow the money from a moneylender. He agreed to pay back $5 a month--for twenty years. His wages at the time were $16 a month. Paul and Alice were poor but not unhappy. They had little enough food, certainly, even before the children began to arrive. Each month Paul paid $5 to the moneylender. He worked hard, never taking a holiday, in time, there were seven mouths to feed. Illness was always with them. It grew serious when the oldest child was eight. The years of hunger weakened the family, because each month Paul paid $5. The details of the sickness were ugly, but the result was this: after twelve years of family life, Paul was alone in the world. He lived alone, except for memories. Work was not now a god for him: it was a pain-killer. Each month he paid, and in time the twenty years ended, From that moment his wages were his own. One day, it was a holiday--he went to the seaside. He sat down on a seat by the sea. A middle-aged woman came and sat down near him. They recognized each other at once. The woman said, "The $600 has been in the bank since the day it was paid to me. It is now $6,000, and I have kept it for you. Will you let me share it with you? "No," said Paul, gently. "Each thousand is a lost life in a desert between us. It can never bring any happiness./

单选题You'd better put these documents in a safe place

单选题Mental Retardation (智力迟钝) Mental retardation is a condition in which people have lower than normal intelligence and are unable to function at the level expected for their age. People with mental retardation are usually born with it, or it develops early in their life. They may also have some difficulty with daily living skills such as learning to read and write and caring for themselves. Doctors and other professionals determine that a person has mental retardation based on their intelligence and how well they can do everyday activities. Intelligence is the ability to learn and understand Levels of intelligence are measured by special tests called intelligence tests. The score a person gets on one of these tests gives a numerical (数字的) measure of a person's intelligence. This is called an intelligence quotient (智商) or IQ. An average score on an IQ test is about 90 to 110. a person with mental retardation will usually score below 75 on an IQ test. The IQ test alone does not determine whether someone is mentally retarded a person must also have trouble with everyday activities such as getting dressed, eating, washing, or learning basic reading, writing, and arithmetic skills. Mental retardation is not a disease itself. It cannot be cured and it's not contagious (传染的). This condition can be caused by several things that injure the brain or don't allow the brain to develop normally. Many times we don't know why a person has mental retardation. Sometimes it may be caused by genes. Genes are chemical units found in every cell. They carry the instructions telling cells what to do. Sometimes, children receive abnormal genes from their parents. a defective gene may also develop spontaneously. Neither parent would have passed on the gene, but the gene changes before the baby develops; Some other problems that can cause mental retardation also happen before a child is born. It is important for the brain to develop properly if a child is to have normal intelligence. "Planning a pregnancy is the most important decision most of us will make in our lifetime. A healthy lifestyle and good medical care should begin before a woman becomes pregnant and continue throughout the pregnancy," says Jodi Rucquoi, a genetic counselor from Connecticut. If a woman abuses alcohol or drugs or doesn't eat well, there is a risk to the developing baby. Also, a premature birth or problems during childbirth can sometimes harm the baby's developing brain. While premature babies are generally fine, there is a greater chance that they may have mental retardation. In some cases, a young child can develop mental retardation after being sick with a serious infection or other illness, or after suffering a bad head injury.

单选题The closer a plant is to its natural state, the less suitable it is to ____.

单选题Challenge for Classical Music The decision of the New York Philharmonic to hire Alan Gilbert as its next music director has been the talk of the classical-music world ever since the sudden announcement of his appointment in 2009. For the most part, the response has been favorable, to say the least. "Hooray! At last!" wrote Anthony Tommasini, a sober-sided classical-music critic. One of the reasons why the appointment came as such a surprise, however, is that Gilbert is comparatively little known. Even Tommasini, who had advocated Gilbert"s appointment in the Times , calls him "an unpretentious musician with no air of the formidable conductor about him." As a description of the next music director of an orchestra that has hitherto been led by musicians like Gustav Mahler and Pierre Boulez, that seems likely to have struck at least some Times readers as faint praise. For my part, I have no idea whether Gilbert is a great conductor or even a good one. To be sure, he performs an impressive variety of interesting compositions, but it is not necessary for me to visit Avery Fisher Hall, or anywhere else, to hear interesting orchestral music. All I have to do is to go to my CD shelf, or boot up my computer and download still more recorded music from iTunes. Devoted concertgoers who reply that recordings are no substitute for live performance are missing the point. For the time, attention, and money of the art-loving public, classical instrumentalists must compete not only with opera houses, dance troupes, theater companies, and museums, but also with the recorded performances of the great classical musicians of the 20th century. There recordings are cheap, available everywhere, and very often much higher in artistic quality than today"s live performances; moreover, they can be "consumed" at a time and place of the listener"s choosing. The widespread availability of such recordings has thus brought about a crisis in the institution of the traditional classical concert. One possible response is for classical performers to program attractive new music that is not yet available on record. Gilbert"s own interest in new music has been widely noted: Alex Ross, a classical-music critic, has described him as a man who is capable of turning the Philharmonic into "a markedly different, more vibrant organization." But what will be the nature of that difference merely expanding the orchestra"s repertoire will not be enough. If Gilbert and the Philharmonic are to succeed, they must first change the relationship between Americans oldest orchestra and the new audience it hopes to attract.

单选题Young Female Chimps Outlearn Their Brothers Young female chimps are faster and better learners than young male chimps, which suggests a new study, echoing learning differences seen in human girls and boys. While young male chimps pass their time playing, young female chimps carefully study their mothers. As a result, they learn how to fish for tasty termite snacks over two years before the boys. Elizabeth Lonsdorf, now at Lincoln Park Zoo in Chicago, US, and colleagues at the University of Minnesota, Saint Paul, spent four years watching how young chimpanzees in the Gombe National Park in Tanzania learned "cultural behavior". The sex differences in learning behavior were "consistent and strikingly apparent", says the team. The researchers point out that similar differences are seen in human children with regard to skills such as writing. "A sex-based learning differences may therefore date back at least to the last common ancestor of chimpanzees and humans," they write in the journal Nature . Chimps make flexible tools from vegetation and then insert them into termite mounds, extract them and then munch the termites clinging onto the tool. The researchers used video cameras to record this feeding behavior and found that each chimp mother had her own technique, such as how she used tools of different lengths. Analysis of the six infants whose ages were known showed that girl chimps were an average of 31 months old when they succeeded in fishing out their termites, where the boy chimps were aged 58 months on average. Females were also more skillful at getting out more termites with every dip and used techniques similar to their mothers while males did not. Instead of studying their mothers，the boy chimps spent a significantly greater amount of time frolicking around the termite mound. Behaviors such as playing or swinging might help the male infants later in life when typically male activities like hunting or fighting for dominance become important, suggest the researchers. Lonsdorf adds that there are just two main sources of animal protein for chimps—the termites or colobus monkeys. "Mature males often hunt monkeys up trees, but females are almost always either pregnant or burdened with a clinging infants. This makes hunting difficult," she says. "Adult females spend more time fishing for termites than males." So becoming proficient at termite fishing could mean adult females eat better. "They can watch their offspring at the same time. The young of both sexes seem to pursue activities related to their adult sex roles at a very young age."

单选题Every year each household in the United States discards approximately a ton of trash.A. fillerB. garbageC. paperD. fuel

单选题On April 23,2004, Holonyak received the $ 500,000 Lemelson -MIT Prize at a ceremony in Washington. This marks the 10th year that the Lemelson--MIT Program at the Massachusetts Institute of Technology (MIT) has given the award to prominent inventors. Lmelson - MIT Prize is aimed to honor famous inventors.A. RightB. WrongC. Not mentioned

单选题 下面有3篇短文，每篇短文后有5道题，每题后面有4个选项。请仔细阅读短文并根据短文回答其后面的问题。{{B}}第一篇{{/B}} {{B}} The Ancient Road Building{{/B}} A quick review of ancient history since men began keeping records of their achievements would show that all the great empire (帝国) builders were also road builders. They knew well that good roads were necessary for keeping the extended empire together. The first of the great empire road builders were the Persians (波斯人). Between 500 and 400 B. C. all the parts of the Persian Empire were connected by roads with the capital city. The main, or "royal", road began near what is now Turkey(土耳其), and ended in Susa. The road had well-built inns where travelers could rest and eat, and tax-houses like those on a modern highway. The people of Greece, unlike the Persians, believed that their city-states could remain independent only if the roads between them were not too good. Besides, the landscape (风景) full of mountains in Greece made road building an extremely difficult job. As a result, the Greeks turned to the sea, and instead of highways, developed sea routes that reached distant lands. By far the greatest of the ancient road builders were the Romans. The Romans, like the Persians before them, recognized the importance of land routes to keep their empire together. At the height of its power, the Roman Empire covered about 2,000,000 square miles. It extended from Spain in the west to the banks of the Caspian Sea(里海) in the east. And from England in the northwest, the empire stretched south to include the coastal lands of North Africa. By about 120 A.D. the Romans had built an extraordinary network of about 50,000 miles of roads. The roads were originally built for military traffic moving from one part of the empire to another, but during periods of peace these same roads were busy with traders and travelers. You can still travel over Roman roads in many parts of Europe today. The Roman engineers knew how to build things that would last and last.

单选题He was a much older tennis player but he had the great advantage of experience.A. strong pointB. weak pointC. disadvantageD. shortcoming

单选题Dichotomy on Species As Gilbert White, Darwin, and others observed long ago, all species appear to have the innate capacity to increase their numbers from generation to generation. The task for ecologists is to untangle the environmental and biological factors that hold this intrinsic capacity for population growth in check over the long run. The great variety of dynamic behaviors exhibited by different population makes this task more difficult: some populations remain roughly constant from year to year; others exhibit regular cycles of abundance and scarcity; still others vary wildly，with outbreaks and crashes that are in some cases plainly correlated with the weather, and in other cases not. To impose some order on this kaleidoscope of patterns, one school of thought proposes dividing populations into two groups. These ecologists posit that the relatively steady populations have "density-dependent" growth parameters; that is, rates of birth, death, and migration which depend strongly on population density. The highly varying populations have "density-independent" growth parameters, with vital rates buffeted by environmental events; these rates fluctuate in a way that is wholly independent of population density. This dichotomy has its uses, but it can cause problems if taken too literally. For one thing, no population can be driven entirely by density-independent factors all the time. No matter how severely or unpredictably birth, death, and migration rates may be fluctuating around their long-term averages, if there were no density-dependent effects, the population would, in the long run, either increase or decrease without bound (barring a miracle by which gains and losses canceled exactly). Put another way, it may be that on average 99 percent of all deaths in a population arise from density-independent causes, and only one percent from factors varying with density. The factors making up the one percent may seem unimportant, and their cause may be correspondingly hard to determine. Yet, whether recognized or not, they will usually determine the long-term average population density. In order to understand the nature of the ecologists" investigation, we may think of the density-dependent effects on growth parameters as the "signal" ecologists are trying to isolate and interpret, one that tends to make the population increase from relatively low values or decrease from relatively high ones, while the density-independent effects act to produce "noise" in the population dynamics. For populations that remain relatively constant, or that oscillate around repeated cycles, the signal can be fairly easily characterized and its effects described, even though the causative biological mechanism may remain unknown. For irregularly fluctuating populations, we are likely to have too few observations to have any hope of extracting the signal from the overwhelming noise. But it now seems clear that all populations are regulated by a mixture of density-dependent and density-independent effects in varying proportions.

单选题The boy felt {{U}}frustrated{{/U}} when he found he had difficulty with most of the math's problems.

单选题His qualifications Usurpass/U the job requirements.

单选题Online gambling is lawful in Nevada.

单选题More about Alzheimer"s Disease Scientists have developed skin tests that may be used in the future to identity people with Alzheimer"s disease and may ultimately allow physicians to predict who is at risk of getting this neurological (神经病学的) disorder. The only current means of diagnosing the disease in a living patient is a long and expensive series of tests that eliminate every other cause of dementia. "Since Alois Alzheimer described the disease nearly a century ago, people have been trying to find a way to accurately diagnose it in its early stages," said Patricia Grady, acting director of the National Institute of Neurological Disorders and Stroke in Bethesda, Maryland. "This discovery, if confirmed, could prove a big step forward in our efforts to deal with and understand the disease." Alzheimer"s is the single greatest cause of mental deterioration in older people, affecting between 2.5 million and 4 million people in the United States alone. The devastating disorder gradually destroys memory and the ability to function, and eventually causes death. There is currently no known treatment for the disease. Researchers discovered that the skin cells of Alzheimer"s patients have defects that interfere with their ability to regulate the flow of potassium in and out of the cells. The fact that the cell defects are present in the skin suggests that Alzheimer"s results from physiological changes throughout the body, and that dementia may be the first noticeable effect of these changes as the defects affect the cells in the brain, scientists said. The flow of potassium is especially critical in cells responsible for memory formation. The scientists also found two other defects that affect the cells" supply of calcium, another critical element. One test developed by researches calls for growing skin cells in a laboratory culture and then testing them with an electrical detector to determine if the microscopic tunnels that govern the flow of potassium are open. Open potassium channels create a unique electrical signature. A spokesman for the Alzheimer"s Association said that if the validity of the diagnostic test can be proven it would be an important development, but he cautioned that other promising tests for Alzheimer"s have been disappointing.

单选题 Natural Medicine Since earliest days, humans have used some kinds of medicines. We know this because humans have survived. Ancient treatments for injury and disease were successful enough to keep humans from dying out completely. They were successful long before the time of modern medicine. Before the time of doctors with white coats and shiny (发亮的) instruments. Before the time of big hospitals with strange and wonderful equipment. Many parts of the world still do not have university-educated doctors. Nor do they have expensive hospitals. Yet injuries are treated. And diseases are often cured, how? By ancient methods. By medicines that might seem mysterious, even magical (有魔力的). Traditional medicines are neither mysterious nor magical, however. Through the centuries, tribal (部落的) medicine men experimented with plants. They found many useful chemicals in the plants. And scientists believe many of these traditional medicines may provide the cure for some of today's' most serious diseases. Experts say almost 80% of the people in the world use plants for health care. These natural medicines are used not just because people have no other form of treatment. They are used because people trust them. In developed areas, few people think about the source of the medicines they buy in a store. Yet many widely-used medicines are from ancient sources, especially plants. Some experts say more than 25% of modern medicines come, in one way or another, from nature. Scientists have long known that nature is really a chemical factory. All living things contain chemicals that help them survive. So scientists' interest in traditional medicine is not new. But it has become an urgent concern. This is because the earth's supply of natural medicines may be dropping rapidly.

单选题The boy is too young to discriminate right from wrong. A. infer B. access C. distinguish D. recognize

单选题Young Adults Who Exercise Get Higher IQ Scores Young adults who are fit have a higher IQ and are more (1) to go on to university, reveals a major new study carried out at the Sahlgrenska Academy and Sahlgrenska University Hospital. The results were recently published in the Proceedings of the National Academy of Sciences (PNAS). The study involved 1.2 million Swedish men doing military service who were born between 1950 and 1976. The research group analysed the (2) of both physical and IQ tests the youngsters took right after they started serving the army. The study shows a clear link (3) good physical fitness and better results for the IQ test. The strongest links are for (4) thinking and verbal comprehension. But it is only fitness that plays a (5) in the results for the IQ test, and not strength. "Being fit means that you also have good heart and lung (6) and that your brain gets plenty of (7) , " says Michael Nilsson, professor at the Sahlgrenska Academy and chief physician at the Sahlgrenska University Hospital. "This may be one of the reasons (8) we can see a clear link with fitness, but not with muscular (9) . We are also seeing that there are growth factors that are important. " By analysing data for twins, the researchers have been (10) to determine that it is primarily environmental factors and not genes that explain the link between fitness and a (11) IQ. "We have also shown that those youngsters who (12) their physical fitness between the ages of 15 and 18 increase their cognitive performance," says Maria Aberg, researcher at the Sahlgrenska Academy and physician at Aby health centre. "This being the case, physical (13) is a subject that has an important place in schools, and is an absolute must if we want to do well in maths and other theoretical subjects. " The researchers have also compared the results from fitness tests (14) national service with the socio-economic status of the men later in (15) . Those who were fit at 18 were more likely to go into higher education, and many secured more qualified jobs.