单选题{{B}}Text 2{{/B}} In the two decades between 1910 and 1930, over ten percent of the Black population of the United States left the South, where most of the Black population had been located, and migrated to northern states, with. the largest number moving, it is claimed, between 1916 and 1918. It has been frequently assumed, but not proved, that the majority of the migrants in what has come to be called the Great Migration came from rural areas and were motivated by two factors: the collapse of the cotton industry, which began in 1898, and increased demand in the North for labor following the cessation of European immigration caused by the outbreak of the First World War in 1914. This assumption has led to the conclusion that the migrants' subsequent lack of economic mobility in the North is tied to rural background, a background that implies unfamiliarity with urban living and a lack of industrial skills. But the question of who actually left the South has never been thoroughly investigated. Although numerous investigations document an exodus (大批出走) from rural southern areas to southern cities prior to the Great Migration, no one has considered whether the same migrants then moved on to northern cities. In 1910 over 600, 000 Black workers, or ten percent of the Black work force, reported themselves to be engaged in "manufacturing and mechanical pursuits", the federal census category roughly encompassing the entire industrial sector. The Great Migration could easily have been made up entirely of this group and their families. It is perhaps surprising to argue that an employed population could be enticed to move, but an explanation lies in the labor conditions then prevalent in the South. About thirty-five percent of the urban Black population in the South was engaged in skilled trades. Some were from the old artisan class of slavery—blacksmiths, masons, carpenters—which had had a monopoly of certain trades, but they were gradually being pushed out by competition, mechanization, and out-date. The remaining sixty-five percent, more recently urbanized, worked in newly developed industries— tobacco, lumber, coal and iron manufacture, and railroads. Wages in the South, however, were low, and Black workers were aware, through labor recruiters and the Black press, that they could earn more even as unskilled workers in the North than they could as artisans in the South. During that period, urban black workers faced competition from the continuing arrival of both Black and White rural workers, who were driven to undercut the wages formerly paid for industrial jobs. Thus a move north would be seen as advantageous to a group that was already urbanized and steadily employed, and the easy conclusion tying their sub-sequent economic problems in the North to their rural background comes into question.

单选题Artificial hearts have long been the stuff of science fiction. In "Robocop", snazzy cardiac devices are made by Yamaha and Jensen, and in "Star Trek", Jean-Luc Picard, captain of the Enterprise, has one implanted in the year 2328. In the present day, however, their history has been more chequered. The first serious attempt to build one happened in the 1980s, when Jarvik-7, made by Robert Jarvik, a surgeon at the University of Utah, captured the world's attention. But Jarvik-7 was a complicated affair that needed to be connected' via tubes to machines outside the body. The patient could not go home, nor even turn around in bed. Various other designs have been tried since, but all were seen as temporary expedients intended to tide a patient over until the real thing became available from a human donor. That may be about to change. This week, America's Food and Drug Administration gave its approval to a new type of artificial heart made by Abiomed, a firm based near Boston. The agency granted a "humanitarian device exemption", a restricted form of approval that will allow doctors to implant the new device in people whose hearts are about to fail but who cannot, for reasons such as intolerance of the immunosuppressive drugs needed to stop rejection, receive a transplant. Such people have a life expectancy of less than a month, but a dozen similarly hopeless patients implanted with Abiomed's heart survived for about five months. Unlike Dr. Jarvik's device, this newfangled bundle of titanium and polyurethane alms to set the patient free. An electric motor revolving up to 10 000 times a minute pushes an incompressible fluid around the Abiomed heart, and that fluid, in turn, pushes the blood--first to the lungs to be oxygenated, and then around the body. Power is supplied by an electric current generated in a pack outside the body. This induces current in the motor inside the heart. All diagnostics are done remotely, using radio signals. There are no tubes or wires coming out of the patient. The charger is usually plugged into the mains, but if armed with a battery it can be carried around for hours in a vest or backpack, thus allowing the patient to roam freely. Most strikingly, the device's internal battery can last half an hour before it needs recharging. That allows someone time to take a shower or even go for a quick swim without having to wear the charger. Abiomed's chairman, Michael Minogue, does not claim that his firm's product will displace human transplants. Even so, the firm has big ambitions. It is already developing a new version that will be 30% smaller (meaning more women can use it) and will last for five years. That should be ready by 2008--320 years earlier than the writers of "Star Trek" predicted.

单选题European farm ministers have ended three weeks of negotiations with a deal which they claim represents genuine reform of the common agricultural policy(CAP). Will it be enough to kickstart the Doha world trade negotiations? On the face of it, the deal agreed in the early hours of Thursday June 26th looks promising. Most subsidies linked to specific farm products are, at last, to be broken--the idea is to replace these with a direct payment to farmers, unconnected to particular products. Support prices for several key products, including milk and butter, are to be cut--that should mean European prices eventually falling towards the world market level. Cutting the link between subsidy and production was the main objective of proposals put forward by Mr. Fischler, which had formed the starting point for the negotiations. The CAP is hugely unpopular around the world. It subsidises European farmers to such an extent that they can undercut farmers from poor countries, who also face trade barriers that largely exclude them from the potentially lucrative European market. Farm trade is also a key feature of the Doha round of trade talks, launched under the auspices of the World Trade Organisation (WTO) in November 2001. Developing countries have lined up alongside a number of industrial countries to demand an end to the massive subsidies Europe pays its farmers. Several Doha deadlines have already been missed because of the EU's intransigence, and the survival of the talks will be at risk if no progress is made by September, when the world's trade ministers meet in Cancun, Mexico. But now even the French seem to have gone along with the deal hammered out in Luxembourg. Up to a point, anyway. The package of measures gives the green light for the most eager reformers to move fast to implement the changes within their own countries. But there is an escape clause of sorts for the French and other reform-averse nations. They can delay implementation for up to two years. There is also a suggestion that the reforms might not apply where there is a chance that they would lead to a reduction in land under cultivation. These let-outs are potentially damaging for Europe's negotiators in the Doha round. They could significantly reduce the cost savings that the reforms might otherwise generate and, in turn, keep European expenditure on farm support unacceptably high by world standards. More generally, the escape clauses could undermine the reforms by encouraging the suspicion that the new package will not deliver the changes that its supporters claim. Close analysis of what is inevitably a very complicated package might confirm the sceptics' fears.

单选题Katherine Conger mentions "Siblings are with us for the whole journey" to show

单选题What happens to nitrogen in body tissues if a diver ascends too quickly?

单选题The case of Napster demonstrates that

单选题Dr. Gordon focused his attention on the Piraha's counting ability because ______.

单选题Modern liberal opinion is sensitive to problems of restriction of freedom and abuse of power. (1) , many hold that a man can be injured only by violating his will, but this view is much too (2) . It fails to (3) the great dangers we shall face in the (4) of biomedical technology that stems from an excess of freedom, from the unrestrained (5) of will. In my view, our greatest problems will be voluntary self-degradation, or willing dehumanization, as is the unintended yet often inescapable consequence of sternly and successfully pursuing our humanization (6) . Certain (7) and perfected medical technologies have already had some dehumanizing consequences. Improved methods of resuscitation have made (8) heroic effort? to "save" the severely ill and injured. Yet these efforts are sometimes only partly successful: They may succeed in (9) individuals, but these individuals may have sever brain damage and be capable of only a less-than-human, vegetating (10) . Such patients have been (11) a death with dignity. Families are forced to bear the burden of a (12) "death watch". (13) the ordinary methods of treating disease and prolonging life have changed the (14) in which men die. Fewer and fewer people die in the familiar surroundings of home or in the (15) of family and friends. This loneliness, (16) , is not confined to the dying patient in the hospital bed. As a group, the elderly are the most alienated members of our society: Not yet (17) the world of the dead, not deemed fit for the world of the living, they are shunted (18) . We have learned how to increase their years, (19) we have not learned how to help them enjoy their days. Yet we continue to bravely and feverishly push back the frontiers (20) death.

单选题Science Fiction can provide students interested in the future with a basic introduction to the concept of thinking about possible futures in a serious way, a sense of the emotional forces in their own cultures that are affecting the shape the future may take, and a multitude of predictions regarding the results of present trends. Although SF seems to take as its future social settings nothing more ambiguous than the current status quo or its totally evil variant, SF is actually a more important vehicle for speculative visions about macroscopic social change. At this level, it is hard to deal with any precision as to when general value changes or evolving social institutions might appear, but it is most important to think about the kinds of societies that could result from the rise of new forms of interaction, even if one cannot predict exactly when they might occur. In performing this "what if ..." function, SF can act as a social laboratory as authors ruminate upon the forms social relationships could take if key variables in their own societies were different, and upon what new belief systems or mythologies could arise in the future to provide the basic rationalizations for human activities. If it is true that most people find it difficult to conceive of the ways in which their society, or human nature itself, could undergo fundamental changes, then SF of this type may provoke one's imagination--to consider the diversity of paths potentially open to society. Moreover, if SF is the laboratory of the imagination, its experiments are often of the kind that may significantly alter the subject matter even as they are being carried out. That is, SF has always had a certain cybernetic effect on society, as its visions emotionally engage the future consciousness of the mass public regarding especially desirable and undesirable possibilities. The shape a society takes in the present is in part influenced by its image of the future; in this way particularly powerful SF images may become self-fulfilling or self-avoiding prophecies for society. For that matter, some individuals in recent years have even shaped their own life styles after appealing models provided by SF stories. The reincarnation and diffusion of SF futuristic images of alternative societies through the media of movies and television may have speeded up and augmented SF's social feedback effects. Thus SF is not only change speculator but change agent, send an echo from the future that is becoming into the present that is sculpting it. This fact alone makes imperative in any education system the study of the kinds of works discussed in this section.

单选题{{B}}Text 2{{/B}} It's seven weeks into the new year. Do you know where your resolution is? If you're like millions of Americans, you probably vowed to lose weight, quit smoking and drink less in the new year. You kicked off January with a commitment to long-term well-being--until you came face-to-face with a cheeseburger. You spent a bundle on a shiny new gym pass. Turns out, it wasn't reason enough for you to actually use the gym. People can make poor decisions when it comes to health--despite their best intentions. It's not easy abiding by wholesome choices (giving up French fries) when the consequences of not doing so (heart disease) seem so far in the future. Most people are bad at judging their health risks: smokers generally know cigarettes cause cancer, but they also tend to believe they're less likely than other smokers to get it. And as any snack-loving dieter can attest, people can be comically inept at predicting their future .behavior. You swear you will eat just one potato chip but don't stop until the bag is empty. So, what does it take to motivate people to stick to the path set by their conscious brain? How can good choices be made to seem more appealing than bad ones? The problem stumps doctors, public-health officials and weight-loss experts, but one solution may spring from an unlikely source. Meet your new personal trainer: your boss. American businesses have a particular interest in personal health, since worker illness costs them billions each year in insurance claims, sick days and high staff turnover. A 2008 survey of major US employers found that 64% consider their employees' poor health decisions a serious barrier to affordable insurance coverage. Now some companies are tackling the motivation problem head on, using tactics drawn from behavioral psychology to nudge their employees to get healthy. "It's a bit paradoxical that employers need to provide incentives for people to improve their own health," says Michael Follick, a behavioral psychologist at Brown University and president of the consultancy Abacus Employer Health Solutions. Paradoxical, maybe, but effective. Consider Amica Mutual Insurance, based in Rhode Island. Arnica seemed to be doing everything right: it boasts an on-site fitness center at its headquarters. It pays toward Weight Watchers and smoking-cessation help, gives gift cards to reward proper prenatal care and offers free flu shots each year. Still, in the mid-2000s, about 7% of the company's insured population, including roughly 3 100 employees and their dependents, had diabetes. "We manage risk. That's our core business," says Scott Boyd, Amica's director of compensation and benefits. But diabetes-related claims from Arnica employees had doubled in four years. "We thought, OK," Boyd says now, "we have to manage these high-risk groups a little better. "

单选题According to the last paragraph, diabetes will