单选题The main difference between deserved-punishment and corrective justice is ______.

单选题Yangtze River flows at a width of up to 2km and an average depth of between 6 and 15m through a large plain with many lakes. This area is______to severe flooding and accumulation of river sediment.

单选题In addition to restraining economic growth, the government was increasingly anxious to tackle its trade ______, which has been a mounting concern in the European Union and the US.

单选题Although any destruction of vitamins caused by food irradiation could be______ the use of diet supplements, there may be no protection from carcinogens that some fear might be introduced into foods by the process.

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 good reason to be concerned—what they were doing that night might soon be made illegal.

单选题What can be learned about the on-line doctors' visits?

单选题Suppose you go into a fruiterer's shop, wanting an apple—you take up one, and on biting it you find it is sour；you look at it, and see that it is hard and green．You take up another one, and that, too, is hard, green, and sour．The shopman offers you a third；but, before biting it, you examine it, and find that it is hard and green, and you immediately say that you will not have it, as it must be sour,like those that you have already tried． Nothing can be more simple than that, you think；but if you will take the trouble to analyze and trace out into its logical elements what has been done by the mind, you will be greatly surprised．In the first place you have performed the operation of induction．You find that, in two experiences, hardness and greenness in apples went together with soumess．It was so in the first case, and it was confirmed by the second．True, it is a very small basis, but stillit is enough from which to make an induction；you generalize the facts, and you expect to find sourness in apples where you get hardness and greenness．You found upon that a general law,that all hard and green apples are sour；and that, so far as it goes, is a perfect induction．Well, having got your natural law in this way,when you are offered another apple which you find it hard and green, you say,"all hard and green apples are sour；this apple is hard and green；therefore, this apple is sour．"That train of reasoning is what logicians call a syllogism．and has all its various parts and terms—its major premises, its minor premises, and its conclusion．And by the help of further reasoning。which, if drawn out, would have to be exhibited in two or three other syllogisms, you arrive at your final determination, "I will not have that apple．"So that, you see, you have, in the first place． established a law by induction, and upon that you have founded a deduction, and reasoned out the special particular case． Well now,suppose, having got your conclusion of the law,that at some times afterwards．you are discussing the qualities of apple with a friend；you will say to him, "It is a very curious thing． but I find that all hard and green apples are sour!"Your friend says to you, "But how do you know that?"You at once reply,"Oh, because I have tried them over and over again, and haye always found them to be so．"Well．if we are talking science instead of common sense, we should call that an experimental verification．And, if still opposed, you go further,and say,"I have heard from people, in Somerset shire and Devon shire, where a large number of apples are grown, and in London, where many apples are sold and eaten, that they have observed the same thing．"It is also found to be the case in Normandy,and in North America．In short, I find it to be the universal experience of mankind wherever attention has been directed to the subject．Whereupon, your friend, unless he is a very unreasonable man, agrees with you, and is convinced that you are quite right in the conclusion you have drawn．He believes, although perhaps he does not know he believes it, that the more extensive verifications have been made．and results of the same kind arrived at—that the more varied the conditions under which the same results are attained, the more certain is the ultimate conclusion, and he disputes the question no further．He sees that the experiment has been tried under all sorts of conditions, as to time, place, and people, with the same result；and he says with you, therefore, that the law you have laid down must be a good one, and he must believe it．

单选题 The range in frequencies of musical sounds is approximately 20-20,000 cycles per second (cy/sec). Some people can hear higher frequencies khan others. Longitudinal waves whose frequencies are higher than those within the audible range are called ultrasonic frequencies. Ultrasonic frequencies are used in sonar for such purposes as submarine detection and depth finding. Ultrasonic frequencies are also being tried for sterilizing food since these frequencies kill some bacteria. Sound waves of all frequencies in the audible range travel at the same speed in the same medium. In the audible range, the higher the frequency of the sound the higher is the pitch. The term supersonic refers to speed greater than sound. An airplane traveling at supersonic speed is moving at a speed greater than the speed of sound in air at that temperature. Mach 1 means a speed equal to that of sound. Mach 2 means a speed equal to twice that of sound, etc. Musical sounds have three basic characteristics: pitch, loudness, and quality or timbre. As was indicated above, pitch is determined largely by the frequency of the wave reaching the ear. The higher the frequency the higher is the pitch. Loudness depends on the amplitude of the wave reaching the ear. For a given frequency, the greater the amplitude of the wave the louder the sound. To discuss quality of sound we need to clarify the concept of overtones. Sounds are produced by vibrating objects. If these objects are given a gentle push, they usually vibrate at one definite frequency producing a pure tone. This is the way a tuning fork is usually used. When objects vibrate freely after a force is momentarily applied, they are said to produce their natural frequency. Some objects, like strings and air columns, can vibrate naturally at more than one frequency at a time. The lowest frequency which an object can produce when vibrating freely is known as the object's fundamental frequency. Other frequencies that the object can produce are known as its overtones. The quality of a sound depends on the number and relative amplitude of the overtones present in the wave reaching the ear.

单选题These goods are sold at reduced prices, ______.

单选题Now researchers are directing more attention to the social and cultural impetus that propelled university graduates into careers in management.(2002年中国人民大学考博试题)

单选题Each passage is followed by some questions or unfinished statements. For each of them, there are four choices marked A, B, C and D. Choose the best answer and mark corresponding letter on Answer Sheet I with a single line through the center. Like many of my generation, I have a weakness for hero worship. At some point, however, we all to question our heroes and our need for them. This leads us to ask: What is a hero? Despite immense differences in cultures, heroes around the world generally share a number of characteristics that instruct and inspire people. A hero does something worth talking about. A hero has a story of adventure to tell and community who will listen. But a hew floes beyond mere fame. Heroes serve powers or principles larger than themselves. Like high-voltage transformers, heroes take the energy of higher powers and step it down so that it can be used by ordinary people. The hero lives a life worthy of imitation. Those who imitate a genuine, they experience life with new depth, enthusiasm, and meaning. A sure test for would-be heroes is what or whom do they serve? What are they willing to live and die for? The answer or evidence suggests they serve only their own fame, they may be famous persons but not heroes. Madonna and Michael Jackson are famous, but who would claim that their fans find life more abundant? Heroes are catalysts (催化剂) for change. They have a vision from the mountaintop. They have the skill and the charm to move the masses. They create new possibilities. Without Gandhi, India might still be part of the British Empire. Without Rosa Parks and Martin Luther King, Jr. , we might still have segregated (隔离的) buses, restaurants, and parks: It may be possible for largescale change to occur without leaders with magnetic personalities, but the pace of change would be slow, the vision uncertain, and the committee meetings endless.

单选题She finds it difficult to ______ her career ambition with her responsibility to her family.

单选题Since the early eighties we have been only too aware of the devastating effects of large-scale environmental pollution. Such pollution is generally the result of poor government planning in many developing nations or the short-sighted, selfish policies of the already industrialized countries which encourage a minority of the world"s population to squander the majority of its natural resources. While events such as the deforestation of the Amazon jungle or the nuclear disaster in Chernobyl continue to receive high...remembered that not all pollution is on this grand scale. A large proportion of the world"s pollution has its source much close to home. Avoiding pollution can be a fulltime job. Try not to inhale traffic fumes, keep away from chemical plants and building-sites; wear a mask when cycling. It is enough to make you want to stay at home. But that, according to a growing body of scientific evidence, would also be a bad idea. Research shows that levels of pollutants such as hazardous gases, particulate matter and other chemical "nasties" are usually higher indoors than out, even in the most polluted cities. Since the average American spends 18 hours indoors for every hour outside, it looks as though many environmentalists may be attacking the wrong target. The latest study, conducted by two environmental engineers, Richard Corsi and Cynthia Howard-Reed, of the University of Texas in Austin, and published in Environmental Science and Technology, suggests that it is the process of keeping clean that may be making indoor pollution worse. The researchers found that baths, showers, dishwashers and washing machines can all be significant sources of indoor pollution, because they extract trace amounts of chemicals from the water that they use and transfer them to the air. Nearly all public water supplies contain very low concentrations of toxic chemicals, most of them left over from the otherwise beneficial process of chlorination. In fact, in many cases, the degree of exposure to toxic chemicals in tap water by inhalation is comparable to the exposure that would result from drinking the stuff. This is significant because many people are so concerned about water-borne pollutants that they drink only bottled water, worldwide sales of which are forecast to reach $ 72 billion by next year. Dr. Corsi"s results suggest that they are being exposed to such pollutants any way simply by breathing at home. The aim of such research is not, however, to encourage the use of gas masks when unloading the washing. Instead, it is to bring a sense of perspective to the debate about pollution. According to Dr. Corsi, disproportionate effort is wasted campaigning against certain forms of outdoor pollution; when there is as much or more cause for concern indoors, fight under people"s noses. Using gas cookers or burning candles, for example, both result in indoor levels of carbon monoxide and particulate matter that are just as high as those to be found outside, amid heavy traffic. Overcrowded classrooms whose ventilation systems were designed for smaller numbers of children frequently contain levels of carbon dioxide that would be regarded as unaccepted on board a submarine. "New car smell" is the result of high levels of toxic chemicals, not cleanliness. Laser printers, computers, carpets and paints all contribute to the noxious indoor mix. The implications of indoor pollution for health are unclear. But before worrying about the problems caused by large-scale industry, it makes sense to consider the small-scale industry, it makes sense to consider the small-scale pollution at home and welcome international debate about this. Scientists investigating indoor pollution will gather next month in Edinburgh at the Indoor Air conference to discuss the problem. Perhaps unwisely, the meeting is being held indoors.

单选题One ______ to define a republic is if a government at least derives all its powers directly or indirectly from the great body of the people.

单选题 Passage 2 There is a question, however, that must be answered before this synthesis is attempted, namely, which are the social tendencies that are general human characteristics? It is easy to be misled in this respect. Much of our social behavior is automatic. Some may be instinctive, that is, organically determined. Much more is based on conditioned responses, that is, determined by situations so persistently and early impressed upon us that' we are no longer aware of the character of the behavior and also ordinarily unaware of the existence or possibility of a different behavior. Thus, a critical examination of what is generally valid for all humanity and what is specifically valid for different cultural types comes to be a matter of great concern to students of society. This is one of the problems that induces us to lay particular stress upon the study of cultures that are historically as little as possible related to our own. Their Study enables us to determine those tendencies that are common to all mankind and those belonging to specific human societies only. Another vista opens if we ask ourselves whether the characteristics of human society are even more widely distributed and found also in the animal world. Relations of individuals or of groups of individuals may be looked at from three points of view; relations to the organic and inorganic outer world, relations among members of the same social group, and what, for lack of a better term, may be designated as subjectively conditioned relations. I mean by this term those attitudes that arise gradually by giving values and meanings to activities, as good or bad, right or wrong, beautiful or ugly, purposive or causally determined. Relations with the organic and inorganic outer world are established primarily by the obtaining of sustenance, protection against rigor of the climate, and geographical limitations of varied kinds. The relations of members among the same social group include the relation of sexes, habits of forming social groups and their forms. Obviously, these phases of human life are shared by animals. Their food requirements are biologically determined and adjusted to the geographical environment in which they live. Acquisition and storage of food are found among animals as well as in man. The need of protection against climate and enemies is also operative in animal society, and adjustment to these needs in the form of nests or dens is common. No less are the relations between members of social groups present in animal life, for animal societies of varied structure occur. It appears, therefore, that a considerable field of social phenomena does not by any means belong to man alone but is shared by the animal world, and the questions must be asked: what traits are common to human and animal societies?Comprehension Questions:

单选题 Many critics of the current welfare system argue that existing welfare regulations foster family instability. They maintain that those regulations, which exclude most poor husband and wife families from Aid to Families with Dependent Children assistance grants, contribute to the problem of family dissolution. Thus, they conclude that expanding the set of families eligible for family assistance plans or guaranteed income measures would result in a marked strengthening of the low-income family structure. If all poor families could receive welfare, would the incidence of instability change markedly? The unhappily married couple, in most cases, remain together out of a sense of economic responsibility for their children, because of the high costs of separation, or because of the consumption benefits of marriage. The formation, maintenance, and dissolution of the family is in large part a function of the relative balance between the benefits and costs of marriage as seen by the individual members of the marriage. The major benefit generated by the creation of a family is the expansion of the set of consumption possibilities. The benefits from such a partnership depend largely on the relative dissimilarity of the resources or basic endowments each partner brings to the marriage. Persons with similar productive capacities have less economic "cement" holding their marriage together. Since the family performs certain function society regards as vital, a complex network of social and legal buttresses has evolved to reinforce marriage. Much of the variation in marital stability across income classes can be explained by the variation in costs of dissolution imposed by society, e. g. division of property, alimony, child support, and the social stigma attached to divorce. Marital stability is related to the costs of achieving an acceptable agreement on family consumption and production and to the prevailing social price of instability in the marriage partners social economic group. Expected AFDC income exerts pressures on family instability by reducing the cost of dissolution. To the extent that welfare is a form of government subsidized alimony payments, it reduces the institutional costs of separation and guarantees a minimal standard of living for wife and children. So welfare opportunities are a significant determinant of family instability in poor neighborhoods, but this is not the result of AFDC regulations that exclude most intact families from coverage. Rather, welfare instability occurs because public assistance lowers both the benefits of marriage and the costs of its disruption by providing a system of government subsidized alimony payments.

单选题The author tells us that

单选题An explanation of an earthquake is a description of the chain of ______ that produces it.