单选题School authorities often refuse to face the problems; government drug-abuse agencies have done all too little to inform the public about it; many physicians still seem unaware of it when they examine teenagers. As a result, parents may still be the last to know that their children have fallen victim to the drug epidemic that has been raging for more than a decade among American's youth. In a 1980 survey of a middle income Cincinnati suburb, 38 percent of the sixth grade and 89 percent of the senior class said they used drugs and/or alcohol; 48% percent of the parents thought their children used alcohol, but only 8 percent thought their children used drugs. Fortunately, there is a few force at work against this epidemic — a nationwide movement of more than 400 parent groups formed to expose and battle drug use among teenagers and preteens. The groups, ranging in size from 15 members to more than 800, have different approaches and widely varying rates of success. Yet this parental crusade is the only major force in the country to have taken active, organized and effective steps aimed at stopping marijuana use. Why the concentration on marijuana? Because it is the illegal drug most used by kids. According to the 1982 National High School Senior Survey, 44 percent of U. S. high-school seniors had smoked pot during the year, and one out of seven of these were daily or near daily smokers. Moreover, in 1982, sociologists Richard Clayton and Harwin Voss reported a close-related connection between pot smoking and subsequent use of cocaine and heroin by young men. Of those, who had smoked pot fewer than 100 times, seven percent had graduated to cocaine, four percent to heroine. But of those who had smoked pot at least 1, 000 times, the equivalent of once a day for those years, 73 percent had gone on to cocaine, and one out of three had graduated to heroin. (Although heroin use among high-school seniors is minimal—0. 6 percent in the past year—multi-drug use is "in". ) Parent groups have found that by stopping their kids from smoking pot, they almost automatically stop all other illegal drugs, and cut down on alcohol use as well. The High School Senior Survey's statistics show that heavy pot smokers tend to be heavy drinkers, while those who do not use pot tend not to drink heavily. Since virtually all over the country teenage "partying" has come to mean "getting smashed and getting stoned" — on anything from pot to pills to hashish, ISD, angel dust and alcohol — some parent groups home in on the partying aspect. Parents Who Care (PWC) was started in November 1979 by 15 Palo Alto, Calif. , parents who were upset by stories of serious drug problems at parties. They held talk sessions with their children and learned, as founder Joann Lundgren observed, that most of them had never been to a party where the main activity was not getting high. The parents' solution: workshops showing kids how to give successful drug-and-alcohol-free parties. Says Margret Ranch, PWC director, "We've seen a change in attitude. Young people are feeling more comfortable saying no. "

单选题Here"s yet another to lose weight. Heavier people are more likely to be killed or seriously injured in car accidents than lighter people. That could mean car designers will have to build in new safety features to compensate for the extra hazards facing overweight passengers. In the US, car manufacturers have already had to redesign air bags so they inflate to lower pressures making them less of a danger to smaller women and children. But no one yet knows what it is that puts overweight passengers at extra risk. A study carried out in Seattle, Washington, looked at more than 26,000 people who had been involved in car crashes, and found that heavier people were at far more risk. People weighing between 100 and 119 kilograms are almost two-and-a-half times as likely to die in a crash as people weighing less than 60 kilograms. And importantly, the same trend held up when the researchers looked at body mass index(BMI)— a measure that takes height as well as weight into account. Someone 1.8 meters tall weighing 126 kilograms would have a BMI of 39, but so would a person 1.5 meters tall weighing 88 kilograms. People are said to be obese if their BMI is 30 or over. The study found that people with a BMI of 35 to 39 are over twice as likely to die in a crash compared with people with BMIs of about 20. It"s not just total weight, but obesity that"s dangerous. While they do not yet know why this is the case, the evidence is worth pursuing, says Charles Mock, a surgeon and epidemiologist at the Harborview Injury Prevention and Research Center in Seattle, who led the research team. He thinks one answer may be for safety authorities to use — heavier crash-test dummies when certifying cars are safe to drive. Crash tests normally use dummies that represent standard-sized males weighing about 78 kilograms. Recently, smaller crash-test dummies have also been used to represent children inside crashing cars. But larger and heavier dummies aren"t used, the US National Highway Traffic Safety Administration in Washington, D.C. told New Scientist. The reasons for the higher injury and death rates are far from clear. Mock speculates that car interiors might not be suitably designed for heavy people. Or obese people, with health problems such as high blood pressure or diabetes, could be finding it tougher to recover from injury.

单选题Women's minds work differently from men's. At least, that is what most men are convinced of. Psychologists view the subject either as a matter of frustration or a joke. Now the biologists have moved into this minefield, and some of them have found that there are real differences between the brains of men and women. But being different, they point out hurriedly, is not the same as being better or worse. There is, however, a definite structural variation between the male and female brain. The difference is in a part of the brain that is used in the most complex intellectual processes — the link between the two halves of the brain. The two halves are linked by a trunk line of between 200 and 300 million nerves, the corpus callosum (胼胝体) . Scientists have found quite recently that the corpus callosum in women is always larger and probably richer in nerve fibers than it is in men. This is the first time that a structural difference has been found between the brains of women and men and it must have some significance. The question is "What?", and, if this difference exists, are there others? Research shows that present-day women think differently and behave differently from men. Are some of these differences biological and inborn, a result of evolution? We tend to think that is the influence of society that produces these differences. But could we be wrong? Research showed that these two halves of the brain had different functions, and that the corpus callosum enabled them to work together. For most people, the left half is used for word-handing, analytical and logical activities; the right half works on pictures, patterns and forms. We need both halves working together. And the better the connections, the more harmoniously the two halves work. And, according to research findings, women have the better connections. But it isn't all that easy to explain the actual differences between skills of men and women on this basis. In schools throughout the world girls tend to be better than boys at "language subjects" and boys better at maths and physics. If these differences correspond with the differences in the hemispheric trunk line, there is an unalterable distinction between the sexes. We shan't know for a while, partly because we don't know of any precise relationship between abilities in school subject and the functioning of the two halves of the brain, and we cannot understand how the two halves interact via the corpus callosum. But this striking difference must have some effect and, because the difference is in the parts of the brain involved in intellect, we should be looking for differences in intellectual processing.

单选题Cells cannot remain alive outside certain limits of temperature, and much narrower limits mark the boundaries of effective functioning. Enzyme(酶)systems of mammals and birds are most efficient only within a narrow range around 37 °C; a departure of a few degrees from this value seriously impairs their functioning. Even though cells can survive wider fluctuations, the integrated actions of bodily systems are impaired. Other animals have a wider tolerance for changes of bodily temperature. For centuries it has been recognized that mammals and birds differ form other animals in the way they regulate body temperatures. Ways of characterizing the difference have become more accurate and meaningful over time, but popular terminology still reflects the old division into warm blooded and cold blooded species; warm blooded include mammals and birds, whereas all over creatures were considered cold blooded. As more species were studied, it became evident that this classification was inadequate. A fence lizard or a desert iguana usually has a body temperature only a degree or two below than of humans and so is not cold. Therefore the next distinction was made between animas that maintain a constant body temperature, called homotherms(同温动物), and those whose body temperature varies with their environment, called poikilotherms(变温动物). But this classification also proved inadequate, because among mammals there are many that vary their body temperatures during hibernation. Furthermore, many invertebrates(无脊椎动物)that live in the depths of the ocean never experience a change in the chill of the deep water, and their body temperatures remain constant. The current distinction is between animals whose body temperature is regulated chiefly by internal metabolic processes and those whose temperature is regulated by, and who get most of their heat from the environment. The former are called endotherms(恒温动物), and the latter are called ectotherms(外温动物). Most ectotherms do regulate their body temperature, and they do so mainly by locomoting to favorable sites or by changing their exposure to external sources of heat. Endotherms(mainly mammals and birds)also regulate their temperature by choosing favorable environment, but primarily they regulate their temperatures by making a variety of internal adjustments.

单选题Have you ever gone to a concert and realized that your seats were right next to the booming speakers? Are you guilty【C1】______turning up the volume on your portable cassette or CD player to drown out the whining of your little brother? Sometimes it's difficult to avoid loud music or noises, but they can be bad news because loud noises can【C2】______temporary or permanent hearing loss. Extremely loud music and noises that go on for long periods of time are common causes of deafness. If a noise is so loud that you have to shout to make yourself【C3】______. there is a【C4】______that the mechanism inside your ear can be injured. Temporary hearing loss can happen after you've been exposed to loud noise for only 15 minutes. If you have temporary hearing loss, you won't be able to hear as【C5】______as you normally can, and you may have tinnitus, which is a fancy word for ringing in the ears. Your ears call feel "full", too. 【C6】______, these things usually go away and your hearing soon return to normal. Permanent hearing loss can happen when someone is exposed to loud noise over and over. Construction workers and people who work in factories must【C7】______ear protectors because the equipment they use can be extremely loud. But even some lawn mowers and power tools can permanently【C8】______a person's ability to hear high-pitched noises and can also give him permanent tinnitus. Listening to extremely loud music over and over can also have the same effect on a person's hearing. And using headphones on a portable cassette or CD player can be dangerous【C9】______if the volume is too high and the headphones are used a lot, the noise can damage the ears. The best way to avoid hearing loss is to wear ear protectors when working with machinery and earplugs when going to a concert. Headphones are OK to wear when you're listening to music; just be sure the volume isn't too high, and give them a rest【C10】______once in a while.

单选题Back in 1896, the Swedish scientist Svante Arrhenius realized that by burning coal we were adding carbon dioxide to the air, and that this would warm the Earth. But he mentioned the issue only in passing (顺便地) , for his calculations suggested it would not become a problem for thousands of years. Others thought that the oceans would soak up any extra CO 2 , so there was nothing much to worry about. That this latter argument has persisted to this day in some quarters highlights our species' propensity (倾向) to underestimate the scale of our impact on the planet. Even the Earth's vast oceans cannot suck up CO 2 as quickly as we can produce it, and we now know the stored CO 2 is acidifying the oceans, a problem in itself. Now a handful of researchers are warning that energy sources we normally think of as innocuous could affect the planet's climate too. If we start to extract immense amounts of power from the wind, for instance, it will have an impact on how warmth and water move around the planet, and thus on temperatures and rainfall. Just to be clear, no one is suggesting we should stop building wind farms on the basis of this risk. Aside from the huge uncertainties about the climatic effects of extracting power from the wind, our present and near-term usage is far too tiny to make any difference. For the moment, any negative consequences on the climate are massively outweighed by the effects of pumping out even more CO 2 . That poses by far the greater environmental threat; weaning ourselves off fossil fuels should remain the priority. Even so, now it is the time to start thinking about the long-term effects of the alternative energy sources we are turning to. Those who have already started to look at these issues report weary, indifferent or even hostile reactions to their work. That's understandable, but disappointing. These effects may be inconsequential, in which case all that will have been wasted is some research time that may well yield interesting insights anyway. Or they may turn out to be sharply negative, in which case the more notice we have, the better. It would be unfortunate to put it mildly, to spend countless trillions replacing fossil-fuel energy infrastructure (基础建设) only to discover that its successor (替代物) is also more damaging than it need be. These climatic effects may even be beneficial. The first, tentative models suggest that extracting large amounts of energy from high-altitude jet streams would cool the planet, counteracting the effects of rising greenhouse gases. It might even be possible to build an energy infrastructure that gives us a degree of control over the weather: turning off wind turbines here, capturing more of the sun's energy there. We may also need to rethink our long-term research priorities. The sun is ultimately the only source of energy that doesn't end up altering the planet's energy balance. So the best bet might be invest heavily in improving solar technology and energy storage—rather than in efforts to harness, say, nuclear fusion. For the moment, all of this remains supposition (推测) . But our species has a tendency to myopia. We have nothing to lose, and everything to gain by taking the long view for a change.

单选题For 150 years scientists have tried to determine the solar constant, the amount of solar energy that reaches the Earth. Yet, even in the most cloud-free regions of the planet, the solar constant cannot be measured precisely. Gas molecules and dust particles in the atmosphere absorb and scatter sunlight and prevent some wavelengths of the light from ever reaching the ground. With the advent of satellites, however, scientists have finally been able to measure the Sun's output without being impeded by the Earth's atmosphere. Solar Max, a satellite from the National Aeronautics and Space Administration (NASA), has been measuring the Sun's output since February 1980. Although a malfunction in the satellite's control system limited its observation for a few years, the satellite was repaired in orbit by astronauts from the space shuffle in 1984. Max's observations indicate that the solar constant is not really constant after all. The satellite's instruments have detected frequent, small variations in the Sun's energy output, generally amounting to no more than 0. 05 percent of the Sun's mean energy output and lasting from a few days to a few weeks. Scientists believe these fluctuations coincide with the appearance and disappearance of large groups of sunspots on the Sun's disk. Sunspots are relatively dark regions on the Sun's surface that have strong magnetic fields and a temperature about 2, 000 degrees Fahrenheit cooler than the rest of the Sun's surface. Particularly large fluctuations in the solar constant have coincided with sightings of large sunspot groups. In 1980, for example, Solar Max's instruments registered a 0. 3 percent drop in the solar energy reaching the Earth. At that time a sunspot group covered about 0. 6 percent of the solar disk, an area 20 times larger than the Earth's surface. Long-term variations in the solar constant are more difficult to determine. Although Solar Max's data have indicated a slow and steady decline in the Sun's output. Some scientists have thought that the satellite's aging detectors might have become less sensitive over the years, thus falsely indicating a drop in the solar constant. This possibility was dismissed, however, by comparing solar Max's observations with data from a similar instrument operating on NASA's Nimbus 7 weather satellite since 1978.

单选题About ten men in every hundred suffer from color blindness in some way; women are luckier only about one in two hundred is affected in this manner. There are different forms of color blindness. A man may not be able to see deep red. He may think that red, orange and yellow are all shades of green. Sometimes a person cannot tell the difference between blue and green. In rare cases an unlucky man may see everything in shades of green—a strange world indeed. In certain occupations color blindness can be dangerous and candidates are tested most carefully. For example, when fighting at night, soldiers use lights of flares to signal to each other. A green light may mean "Advance" and a red light may mean: "Danger! Keep back!" You can see what will happen if somebody thinks that red is green! Color blindness in human beings is a strange thing to explain. In a single eye there are millions of very small things called "cones". These help to see in a bright light and to tell the difference between colors. There are also millions of "rods" but these are used for seeing when it is nearly dark. They show us shape but not color. Wait until it is dark tonight, then go outside. Look round you and try to see what colors you can recognize. Birds and animals which hunt at night have eyes which contain few or no cones at all, so they cannot see colors. As far as we know, bats and adult owls cannot see colors at all only light and dark shapes. Similarly cats and dogs cannot see colours as well as we can. Insects can see ultra violet rays which are invisible to us, and some of them can even see X rays. The wings of a moth may seem grey and dull to us, but to insects they may appear beautiful, showing colors which we cannot see. Scientists know that there are other colors around us which insects can see but which we cannot see. Some insects have favorite colors. Mosquitoes like blue, but do not like yellow. A red light will not attract insects but a blue lamp will.

单选题It is a natural marvel. All of the life of the earth dies, all the time, in the same volume as the new life that dazzles us each morning, each spring. In our way, we human beings conform as best we can to the rest of nature. The obituary pages tell us of the news that we are dying away, while the birth announcements inform us of our replacement , but we get no grasp from this of the enormity of scale. There are 3 billion of us on the earth, and all 3 billion must be dead, on a schedule, within this lifetime. The vast mortality, involving something over 50 million of us each year, takes place in relative secrecy. We can only really know of the deaths in our households, or among our friends. These, detached in our minds from all the rest, we take to be unnatural events, anomalies, outrages. We streak of our own dead in low voices; struck down, we say, as though visible death can only occur for cause, by disease or violence , avoidably. We send off for flowers, grieve, make ceremonies, scatter bones, unaware of the rest of the 3 billion on the same schedule. All of that immense mass of flesh and bone and consciousness will disappear by absorption into the earth, without recognition by the transient survivors . Less than a half century from now, our replacements will have more than doubled the numbers. It is hard to see how we can continue to keep the secret, with such multitudes doing the dying. We will have to give up the notion that death is catastrophe, or detestable, or avoidable, or e-ven strange. We will need to learn more about the cycling of life in the rest of the system, and about our connection to the process. Everything that comes alive seems to be in trade for something that dies, cell for cell. There might be some comfort in the recognition of synchrony, in the information that we all go down together, in the best of company.

单选题Conventional wisdom about conflict seems pretty much cut and dried. Too little conflict breeds apathy (冷漠) and stagnation (呆滞) . Too much conflict leads to divisiveness (分裂) and hostility. Moderate levels of conflict, however, can spark creativity and motivate people in a healthy and competitive way. Recent research by Professor Charles R. Schwenk, however, suggests that the optimal level of conflict may be more complex to determine than these simple generalizations. He studied perceptions of conflict among a sample of executives. Some of the executives worked for profit-seeking organizations and others for not-for-profit organizations. Somewhat surprisingly, Schwenk found that opinions about conflict varied systematically as a function of the type of organization. Specifically, managers in not-for-profit organizations strongly believed that conflict was beneficial to their organizations and that it promoted higher quality decision making than might be achieved in the absence of conflict. Managers of for-profit organizations saw a different picture. They believed that conflict generally was damaging and usually led to poor-quality decision making in their organizations. Schwenk interpreted these results in terms of the criteria for effective decision making suggested by the executives. In the profit-seeking organizations, decision-making effectiveness was most often assessed in financial terms. The executives believed that consensus rather than conflict enhanced financial indicators. In the not-for-profit organizations, decision-making effectiveness was defined from the perspective of satisfying constituents. Given the complexities and ambiguities associated with satisfying many diverse constituents executives perceived that conflict led to more considered and acceptable decisions.

单选题For the past several years, the Sunday newspaper supplement Parade has featured a column called "Ask Marilyn. " People are invited to query Marilyn vos Savant, who at age 10 had tested at a mental level of someone about 23 years old; that gave her an IQ of 228-the highest score ever recorded. IQ tests ask you to complete verbal and visual analogies, to envision paper after it has been folded and cut, and to deduce numerical sequences, among other similar tasks. So it is a bit confusing when vos Savant fields such queries from the average Joe (whose IQ is 100) as, What's the difference between love and fondness? Or what is the nature of luck and coincidence? It's not obvious how the capacity to visualize objects and to figure out numerical patterns suits one to answer questions that have eluded some of the best poets and philosophers. Clearly, intelligence encompasses more than a score on a test. Just what does it mean to be smart? How much of intelligence can be specified, and how much can we learn about it from neurology, genetics, computer science and other fields? The defining term of intelligence in humans still seems to be the IQ score, even though IQ tests are not given as often as they used to be. The test comes primarily in two forms: the Stanford-Binet Intelligence Scale and the Wechsler Intelligence Scales (both come in adult and children's version). Generally costing several hundred dollars, they are usually given only by psychologists, although variations of them populate bookstores and the World Wide Web. Superhigh scores like Vos Savant's are no longer possible, because scoring is now based on a statistical population distribution among age peers, rather than simply dividing the mental age by the chronological age and multiplying by 100. Other standardized tests, such as the Scholastic Assessment Test (SAT) and the Graduate Record Exam (GRE), capture the main aspects of IQ tests. Such standardized tests may not assess all the important elements necessary to succeed in school and in life, argues Robert J. Sternberg. In his article "How Intelligent Is Intelligence Testing?" Sternberg notes that traditional test best assess analytical and verbal skills but fail to measure creativity and practical knowledge, components also critical to problem solving and life success. Moreover, IQ test do not necessarily predict so well once populations or situations change. Research has found that IQ predicted leadership skills when the tests were given under low-stress conditions, but under high-stress conditions, IQ was negatively correlated with leadership-that is, it predicted the opposite. Anyone who has toiled through SAT will testify that test-taking skill also matters, whether it knows when to guess or what questions to skip.

单选题At 9:00 in the evening on January 29, just as President George W. Bush was about to begin his first State of the Union address, I gathered with three anxious scientists in a small, windowless laboratory in Worcester, Massachusetts. We were at Advanced Cell Technology—a privately owned biotechnology company that briefly made international headlines last fall by publishing the first scientific account of cloned human embryos. The significance of the achievement was debatable: the company's most successful embryo had reached only six cells before it stopped dividing (one other had reached four cells another had reached two)—a fact that led to a widespread dismissal, in the media and the scientific community, of ACT's "breakthrough". The work was largely judged to be preliminary, inconsequential and certainly not worthy of headlines. Many people in political and religious circles, however, had a decidedly different view. They deemed ACT's work an ethical transgression of the highest order and professed shock, indignation, and horror. Nonetheless, ACT was pressing ahead—which was why I had come to the company's cloning lab that night in January. The door to the lab was locked; a surveillance camera mounted on the ceiling watched our every move, and the mood was at once urgent and tense. A human egg, retrieved just hours earlier from a young donor, was positioned under a microscope, its image glowing on a nearby video monitor. The egg's chromosomes would shortly be removed, and the scientists in the room would attempt to fuse what remained of the egg with a human skin cell. If the procedure succeeded, the result would be a cloned human embryo. Skin cell to embryo—it's one of the most remarkable quick—change scenarios modern biology has to offer. It's also one of the most controversial. Since the announcement, in 1997, of the cloning of the sheep Dolly, attempts to use human cells for cloning have provoked heated debate in the United States, separating those who have faith in the promise of the new technology from those who envision its dark side and unintended consequences. Crucial to the debate is the fact that human cloning research falls into two distinct categories: reproductive cloning, a widely frowned-on effort that aims to produce a fully formed child; and therapeutic cloning, a scientifically reputable procedure that takes place entirely at the microscopic level and is designed to advance medical therapies and cure human ailments. The two start out the same way—with a new embryo in a Petri dish. But the scientists I was observing in the lab had no intention of creating a person. Instead they were embarking on an experiment that, if successful, would be a first step toward creating radical new cures for patients like the donor of the skin cell—Trevor Ross (not his real name), a two-year-old boy afflicted with a rare and devastating genetic disease. The mood in the lab was tense in part because of the uncertain outcome of the experiment. But it was also tense because of concern over what President Bush might say about cloning in his address to the nation. A radio in one corner of the room was tuned to the broadcast as the scientists began their work, and they were listening carefully: in perhaps no other fields of science are researchers as mindful of which way the political winds are blowing. The ACT scientists had a good reason to be concerned—what they were doing that night might soon be made illegal.

单选题Our understanding of cities in anything more than casual terms usually starts with observations of their spatial form and structure at some point or cross-section in time. This is the easiest way to begin, for it is hard to assemble data on how cities change through time, and, in any case, our perceptions often betray us into thinking of spatial structures as being resilient and long lasting. Even where physical change is very rapid, this only has an impact on us when we visit such places infrequently , after years away. Most of our urban theory, whether it emanates from the social sciences or engineering, is structured around the notion that spatial and social structures change slowly, and are sufficiently inert for us to infer reasonable explanations from cross-sectional studies. In recent years, these assumptions have come to be challenged, and in previous editorials I have argued the need for a more temporal emphasis to our theories and models, where the emphasis is no longer on equilibrium but on the intrinsic dynamics of urban change. Even these views, however, imply a conventional wisdom where the real focus of urban studies is on processes that lead to comparatively slow changes in urban organization, where the functions determining such change are very largely routine, accomplished over months or years, rather than any lesser cycle of time. There is a tacit assumption that longer term change subsumes routine change on a day-to-day or hour-by-hour basis, which is seen as simply supporting the fixed spatial infrastructures that we perceive cities to be built around. Transportation modeling, for example, is fashioned from this standpoint in that routine trip-making behavior is the focus of study, its explanation being central to the notion that spatial structures are inert and long lasting.

单选题Are some people born clever and others born stupid? Or is intelligence developed by our environment and our experiences? Strangely【C1】______, the answer to both these questions is yes. To some extent our intelligence is given us at birth, and no amount of special education can make a genius【C2】______a child born with low intelligence. On the other hand, a child who lives in boring environment will develop his intelligence less than the one who lives in rich and varied surroundings. Thus the【C3】______of a person" s intelligence are fixed at birth, but whether or not he reaches those limits will depend on his【C4】______This view, not held by most experts, can be supported in a number of ways. It is easy to show that intelligence is to some extent【C5】______we are born with. The closer the blood relationship between two people, the closer they are likely to be in intelligence. Thus if we take two unrelated people【C6】______, it is likely that their degrees of intelligence will be completely different. If on the other hand we take two identical twins they will likely be as intelligent as each other. Relations like brothers and sisters, parents and children, usually have【C7】______intelligence and this clearly suggests that intelligence depends on birth. 【C8】______now that we take identical twins and put them in different environments. We might send one, for example to a university and the other to a factory where the work is boring. We would soon find differences in intelligence developing, and this indicates that environment【C9】______birth plays a part. This conclusion is also suggested by the【C10】______that people who live in close contact with each other,but who are not related at all, are likely to have similar degrees of intelligence.

单选题Parents are on a journey of discovery with each child whose temperament, biology, and sleep habits result in a unique sleep-wake pattern. It can be frustrating when children's sleep habits do not conform to the household schedule. Helping the child develop good sleep habits in childhood takes time and parental attention, but it will have beneficial results throughout life. An understanding of the changing patterns of the typical sleep-wake cycle in children will help alleviate any unfounded concerns. Maintaining a sleep diary for each child will provide the parents with baseline information in assessing the nature and severity of childhood sleep problems. Observant patents will come to recognize unusual sleep disruptions or those that persist or intensify. Developmental changes throughout childhood bring differences in the sleep-wake cycle and in the type and frequency of parasomnias that may interrupt sleep. Medical consultation to rule out illness, infection of injury is prudent if the child's sleep problems prevent adequate sleep and result in an ongoing sleep deficit. As reported by News-Medical in Child Health News, children's sleep problems should be taken seriously as they may be a "'marker' for predicting later risk of early adolescent substance use. In the same article University of Michigan psychiatry professor Kirk Brower, who has studied "the interplay of alcohol and sleep in adults" stressed that "The finding does not mean there's a cause-and-effect relationship. " Consultation with a child psychologist may be helpful if frightening dreams intensify and become more frequent as this may indicate a particular problem or life circumstance that needs to be changed or one that the child may need extra help working through. Most childhood sleep disturbance will diminish over time as the brain matures and a regular sleep-wake cycle is established. Parental guidance is crucial to the development of healthy sleep habits in children.

单选题The truth may well be self-evident that all humans are created equal, but one thing our Maker did not endow us with equally is the speed at which we take in words on the printed page. This seems not so much a function of brains as of how efficiently the machinery works. A few of us are industrial vacuum cleaners, able to suck up "The Decline and Fall of the Roman Empire" in a matter of hours. At the other extreme are the lint-pickers, those who must lip-read even Danielle Steel. The rest of us are left to carpet-sweep at the rate of three or four words at a glance, and dream of the hours that would be saved if only we were better endowed. Onto this uneven field charged Evelyn Wood back in the late 1950' s. She was convinced that with a little pushing, all of us, even the lint-pickets, could be transformed into vacuum cleaners. All we had to do was stop saying the words out loud in our heads—" subvocalizing" , she called it— and to stop pausing to reread words as our minds drifted away. The point was to start consuming print in bites instead of nibble. To do this, Wood wanted us to drag our fingers down the middle of the page to act as pacers, to be rabbits for the greyhounds of our eyes. She promised that the words wouldn' t blur; the faster we went, the more we would take in. Did her method really work? Multitudes believed it did and flocked to her Evelyn Wood Reading Dynamics Institutes as they spread across the land. Presidents of the United States packed members of their staffs off to her schools, the better to keep from drowning in Presidential memos. Her students devoured George Orwell' s "Animal Farm" at the rate of 1,400 words a minute. Wood had guaranteed that her method worked on all manner of material. Not likely. So there had to be a drop of snake oil in the ointment. Still the essence of Wood' s notion was sound.

单选题WHY SHOULD anyone buy the latest volume in the ever-expanding Dictionary of National Biography? I do not mean that it is bad, as the reviewers will agree. But it will cost you 65 pounds. And have you got the rest of volumes? You need the basic 22 plus the largely decennial supplements to bring the total to 31. Of course, it will be answered, public and academic libraries will want the new volume. After all, it adds 1,068 lives of people who escaped the net of the original compilers. Yet in 10 year"s time a revised version of the whole caboodle, called the New Dictionary of National Biography, will be published. Its editor, Professor Colin Matthew, tells me that he will have room for about 50,000 lives, some 13,000 more than in the current DNB. This rather puts the 1,068 in Missing Persons in the shade. When Dr. Nicholls wrote to The Spectator in 1989 asking for name of people whom readers had looked up in the DNB and had been disappointed not to find, she says that she received some 100,000 suggestions.(Well, she had written to "other quality newspapers" too.)As soon as her committee had whittled the numbers down, the professional problems of an editor began. Contributors didn"t file copy on time; some who did send too much: 50,000 words instead of 500 is a record, according to Dr. Nicholls. There remains the dinner-party game of who"s in, who"s out. That is a game that the reviewers have played and will continue to play. Criminals were my initial worry. After all, the original edition of the DNB boasted: Malefactors whose crimes excite a permanent interest have received hardly less attention than benefactors. Mr. John Gross clearly had similar anxieties, for he complains that, while the murderer Christie is in, Crippen is out. One might say in reply that the injustice of the hanging of Evans instead of Christie was a force in the repeal of capital punishment in Britain, as Ludovie Kennedy(the author of Christies entry in Missing Persons)notes. But then Crippen was reputed as the first murderer to be caught by telegraphy(he had tried to escape by ship to America). It is surprising to find Max Miller excluded when really not very memorable names get in. There has been a conscious effort to put in artists and architects from the Middle Ages. About their lives not much is always known. Of Hugo of Bury St Edmunds, a 12th-century illuminator whose dates of birth and death are not recorded, his biographer comments: "Whether or not Hugo was a wall-painter, the records of his activities as carver and manuscript painter attest to his versatility". Then there had to be more women, too(12 percent, against the original DBN"s 3), such as Roy Strong"s subject, the Tudor painter Levina Teerlinc, of whom he remarks: "Her most characteristic feature is a head attached to a too small, spindly body. Her technique remained awkward, thin and often cursory." Doesn"t seem to qualify her as a memorable artist. Yet it may be better than the record of the original DNB, which included lives of people who never existed(such as Merlin)and even managed to give thanks to J. W. Clerke as a contributor, though, as a later edition admits in a shamefaced footnote, "except for the entry in the List of Contributors there is no trace of J. W Clerke".

单选题It is common to think that other animals are ruled by instinct whereas humans lost their instincts and ruled by reason, and that this is why we are so much more flexibly intelligent than other animals. William James, in his book Principles of Psychology, took the opposite view. He argued that human behavior is more flexibly intelligent than that of other animals because we have more instincts than they do, not fewer. We tend to be blind to the existence of these instincts, however, precisely because they work so well— because they process information so effortlessly and automatically. They structure our thought so powerfully, he argued, that it can be difficult to imagine how things could be otherwise. As a result, we take normal behavior for granted. We do not realize that normal behavior needs to be explained at all. This instinct blindness makes the study of psychology difficult. To get past this problem, James suggested that we try to make the natural seem strange. It takes a mind debauched by learning to carry the process of making the natural seem strange, so far as to ask for the why of an instinctive human act. In our view, William James was right about evolutionary psychology. Making the natural seem strange is unnatural—it requires the twisted outlook seen, for example, in Gary Larson cartoons. Yet it is a central part of the enterprise. Many psychologists avoid the study of natural competences, thinking that there is nothing there to be explained. As a result, social psychologists are disappointed unless they find a phenomenon that would surprise their grandmothers and cognitive psychologists spend more time studying how we solve problems we are bad at, like learning math or playing chess, than ones we are good at. But our natural competences — our abilities to see, to speak, to find someone beautiful, to reciprocate a favor, to fear disease, to fall in love, to initiate an attack, to experience moral outrage, to navigate a landscape, and myriad others — are possible only because there is a vast and heterogeneous array of complex computational machinery supporting and regulating these activities. This machinery works so well that we don't even realize that it exists—we all suffer from instinct blindness. As a result, psychologists have neglected to study some of the most interesting machinery in the human mind.

单选题This issue of Science contains announcements for more than 100 different Gorgon Research Conferences, on topics that range from atomic physics to developmental biology. The brainchild (某人的主意) of Neil Gordon of Johns Hopkins University, these week-long meetings are designed to promote intimate, informal discussions of frontier science. Often confined to fewer than 125 attendees, they have traditionally been held in remote places with minimal distractions. Beginning in the early 1960s, I attended the summer Nucleic Acids Gordon Conference in rural New Hampshire, sharing austere (简朴的) dorm facilities in a private boy's school with randomly assigned roommates. As a beginning scientist, I found the question period after each talk especially fascinating, providing valuable insights into the personalities and ways of thinking of many senior scientists whom I had not encountered previously. Back then, there were no cellphones and no Internet, and all of the speakers seemed to stay for the entire week. During the long, session-free afternoons, graduate students mingled freely with professors. Many lifelong friendships were begun, and — as Gordon intended — new scientific collaborations began. Leap forward to today, and every scientist can gain immediate access to a vast store of scientific thought and to millions of other scientists via the Internet. Why, nevertheless, do in-person scientific meetings remain so valuable for a life in science? Part of the answer is that science works best when there is a deep mutual trust and understanding between the collaborators, which is hard to develop from a distance. But most important is the critical role that face-to-face scientific meetings play in stimulating a random collision of ideas and approaches. The best science occurs when someone combines the knowledge gained by other scientists in non-obvious ways to create a new understanding of how the world works. A successful scientist needs to deeply believe, whatever the problem being tackled, that there is always a better way to approach that problem than the path currently being taken. The scientist is then constantly on the alert for new paths to take in his or her work, which is essential for making breakthroughs. Thus, as much as possible, scientific meetings should be designed to expose the attendees to ways of thinking and techniques that are different from the ones that they already know.

单选题In Mr. Allen" s high school class, all the students have to "get married". However, the wedding ceremonies are not real ones but【C1】______These mock ceremonies sometimes become so【C2】______that the loud laughter drowns out the voice of the " minister". Even the two students getting married often begin to giggle. The teacher, Mr. Allen, believes that marriage is a difficult and serious business. He wants young people to understand that there are many changes that【C3】______take place after marriage. He believes that the need for these psychological and financial【C4】______should be understood before people marry. Mr. Allen doesn"t only introduce his students to major problems【C5】______in marriage such as illness or unemployment. He also exposes them to nitty-gritty problems they will face every day. He wants to introduce young people to all the trials and【C6】______that can strain a marriage to the breaking point. He even【C7】______his students with the problems of divorced men who must pay child support money for their wives. It has been upsetting for some of the students to see the problems that a married couple often faces.【C8】______they took the course, they had not worried much about the problems of marriage. However, both students and parents feel that Mr. Allen" s course is valuable and have【C9】______the course publicly. Their statements and letters supporting the class have【C10】______the school to offer the course again.