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单选题"Citizenship classes" (Paragraph 4) were offered because Americans

单选题FLOODS. DROUGHTS. HURRICANES. TWISTERS. Are all the bizarre weather extremes we've been having lately normal fluctuations in the planet's atmospheric systems? Or are they a precursor of the kind of climactic upheavals that can be expected from the global warming caused by the continued buildup of CO2 and the other so-called greenhouse gases? Scientists are still not sure. But one of the effects of the unusual stretch of weather over the past 15 years has been to alert researchers to a new and perhaps even more immediate threat of the warming trend: the rapid spread of disease-bearing bugs and pests. Climate change, whether natural or man-made, may already be spreading disease and pestilence, according to a host of new studies, including a major report being prepared by the World Health Organization and other international institutions for release this season. Malaria, for example, has been flourishing in recent years owing to unusually hot weather. Similarly, climate disruptions may be giving new life to such ancient scourges as yellow fever, meningitis and cholera, while fostering the spread of emerging diseases like hantavirus. Underlying all these outbreaks is the same Darwinian mechanism: unusual weather such as dry spells in wet areas or torrential rains in normally dry spots tends to favor so-called opportunistic pests — rodents, insects, bacteria, protozoa, viruses — while making life more difficult for the predators that usually control them. Episodes of extreme weather are routinely followed by outbreaks of plagues, both old and new. Of all the infectious diseases humans will have to contend with as the world gets warmer, malaria may be the worst. Malaria is already the world's most widespread mosquito-borne illness. Rising temperatures will not only expand the range of Anopheles mosquitoes, but make them more active biters as well. Paul Epstein, an epidemiologist with the Harvard School of Public Health, notes that a temperature rise of 2℃ would more than double mosquito metabolism, forcing them to feed more often. A 2℃ rise in global temperatures could also expand malaria's domain from 42% to 60% of the planet. When temperatures rise above 40℃, mosquitoes begin to die off — but at those temperatures, so do people and the crops on which they live.

单选题Why didn't silent reading become common before the nineteenth century?

单选题Learning science helps children to develop ways of understanding the world around them. For this they have to build up concepts which help them link their experiences together, they must learn ways of gaining and organizing information and of applying and testing ideas. This contributes not only to children's ability to make better sense of things around them, but prepares them to deal more effectively with wider decision-making and problem-solving in their lives. Science is as basic a part of education as numeracy and literacy, it daily becomes more important as the complexity of technology increases and touches every part of our lives. Learning science can bring a double benefit because science is both a method and a set of ideas, both a process and product. The processes of science provide a way of finding out information, testing ideas and see- king explanations. The products of science are ideas which can be applied in helping to understand new experiences. The word "can" is used advisedly here, it indicates that there is the potential to bring these benefits but no guarantee that they will be realized without taking the appropriate steps. In learning science the development of the process side and the product side must go hand in hand, they are totally interdependent. This has important implications for the kinds of activities children need to encounter in their education But before pursuing these implications, there are still two further important points which underline the value of including science in primary education. The first is that whether we teach children science or not, they will ha developing ideas about the world around from their earliest years. If these ideas are based on casual observation, non-investigated events and the acceptance of hearsay, than they are likely to be non-scientific. "everyday" ideas. There are plenty of such ideas around for children to pick up. My mother believed (and perhaps still does despite my efforts) that if the sun shines through the window on to the fire it puts the fire out, that cheese maggots f a common encounter in her youth when food was sold unwrapped) are made of cheese and develop spontaneously from it, that placing a lid on a pan of boiling water makes it boil at a lower temperature, that electricity travels more easily if the wires are not twisted. Similar myths still abound and no doubt influence children's attempts to make sense of their experience. As well as hearsay, left to themselves, children will also form some ideas which seem unscientific; for example, that to make something move requires a force but to stop it needs no force. All these ideas could easily be put to the test; children's science education should make children want to do it. Then they not only have the chance to modify their ideas, but they learn to be sceptical about so-called "truths" until these have been put to the test. Eventually they will realize that all ideas are working hypotheses which can never be proved right, but are useful as long as they fit the evidence of experience and experiment. The importance of beginning this learning early in children's education is twofold. On the one hand the children begin to realize that useful ideas must fit the evidence; on the other hand they are less likely to form and to accept everyday ideas which can be shown to be in direct conflict with evidence and scientific concepts. There are research findings to show that the longer the non-scientific ideas have been held, the more difficult they are to change. Many children come to secondary science, not merely lacking the scientific ideas they need, but possessing alternative ideas which are a barrier to understanding their science lessons. The second point about starting to learn science, and to learn scientifically, at the primary level is connect- ed with attitudes to the subject. There is evidence that attitudes to science seem to be formed earlier than to most other subjects and children tend to have taken a definite position with regard to their liking of the subject by the age of 11 or 12. Given the remarks just made about the clash between the non-scientific ideas that many children bring to their secondary science lessons and the scientific ideas they are assumed to have, it is not surprising that many find science confusing and difficult. Such reactions undoubtedly affect their later performance in science. Although there is a lesson here for secondary science, it is clear that primary science can do much to avoid this crisis at the primary/secondary interface

单选题 Specialisation can be seen as a response to the problem of an increasing accumulation of scientific knowledge. By splitting up the subject matter into smaller units, one man could continue to handle the information and use it as the basis for further research. But specialisation was only one of a series of related developments in science affecting the process of communication. Another was the growing professionalisation of scientific activity. No clear-cut distinction can be drawn between professionals and amateurs in science: exceptions can be found to any rule. Nevertheless, the word "amateur" does carry a connotation that the person concerned is not fully integrated into the scientific community and, in particular, may not fully share its values. The growth of specialisation in nineteenth century, with its consequent requirement of a longer, more complex training, implied greater problems for amateur participation in science. The trend was naturally most obvious in those areas of science based especially on a mathematical or laboratory training, and can be illustrated in terms of the development of geology in the United Kingdom. A comparison of British geological publications over the last century and a half reveals not simply an increasing emphasis on the primacy of research, but also a changing definition of what constitutes an acceptable research paper. Thus, in the nineteenth century, local geological studies represented worthwhile research in their own right; but, in the twentieth century, local studies have increasingly become acceptable to professionals only if they incorporate, and reflect on, the wider geological picture. Amateurs, on the other hand, have continued to pursue local studies in the old way. The overall result has been to make entrance to professional geological journals harder for amateurs, a result that has been reinforced by the widespread introduction of refereeing, first by national journals in the nineteenth century and then by several local geological journals in the twentieth century. As a logical consequence of this development, separate journals have now appeared aimed mainly towards either professional or amateur readership. A rather similar process of differentiation has led to professional geologists coming together nationally within one or two specific societies, whereas the amateurs have tended either to remain in local societies or to come together nationally in a different way. Although the process of professionalisation and specialisation was already well under way in British geology during the nineteenth century, its full consequences were thus delayed until the twentieth century. In science generally, however, the nineteenth century must be reckoned as the crucial period for this change in the structure of science.

单选题People appear to be born to compute. The numerical skills of children develop so early and so inexorably that it is easy to imagine an internal clock of mathematical maturity guiding their growth. Not long after learning to walk and talk, they can set the table with impressive accuracy one plate, one knife, one spoon, one fork, for 'each of the five chairs. Soon they are capable of noting that they have placed five knives, five spoons, and five forks on the table and, a bit later, that this amounts to fifteen pieces of silverware. Having thus mastered addition, they move on to subtraction. It seems almost reasonable to expect that if a child were secluded on a desert island at birth and returned seven years later, he or she could enter a second-grade mathematics class without any serious problems of intellectual adjustment. Of course, the truth is not so simple. In this century, the work of cognitive psychologists has illuminated the subtle forms of daily learning on which intellectual progress depends. Children were observed as they slowly grasped--or, as the case might be, bumped into--concepts that adults take for granted, as they refused, for instance, to concede that quantity is unchanged as water pours from a short stout glass into a tall thin one. Psychologists have since demonstrated that young children, when asked to count the pencils in a pile, readily report the number of blue or red pencils, but must be coaxed into finding the total. Such studies have suggested that the rudiments of mathematics are mastered gradually, and with effort. They have also suggested that the very concept of abstract numbers--the idea of a oneness, a twoness, a threeness that applies to any class of objects and is prerequisite for doing anything more mathematcally demanding than setting a table--is itself far from innate.

单选题Which city has not been praised by IOC after hosting the Olympic Games so far?

单选题This passage states that a person is really asleep only

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单选题How did Ward gain her position of authority?