单选题{{B}}Text 1{{/B}} In recent years, there has been a steady assault on salt from the doctors: salt is bad for you-- regardless of your health. Politicians also got on board. "There is a direct relationship," US congressman Neal Smith noted, "between the amount of sodium a person consumes and heart disease, circulatory disorders, stroke and even early death." Frightening, if true! But many doctors and medical researchers are now beginning to feel the salt scare has gone too far. "All this hue and cry 'about eating salt is unnecessary," Dr Dustan insists. "For most of us it probably doesn't make much difference how much salt we eat." Dustan' s most recent short- term study of 150 people showed that those with normal blood pressure experienced no change at all when placed on an extremely low-salt diet, or later when salt was reintroduced. Of the hypertensive subjects, however, half of those on the low-salt diet did experience a drop in blood pressure, which returned to its previous level when salt was reintroduced. "An adequate to somewhat excessive salt intake has probably saved many more lives than it has cost in the general population," notes Dr. John H. Laragh. "So a recommendation that the whole population should avoid salt makes no sense." Medical experts agree that everyone should practice reasonable "moderation" in salt consumption. For the average person, a moderate amount might run from four to ten grams a day, or roughly 1/2 to 1/3 of a teaspoon. The equivalent of one to two grams of this salt allowance would come from the natural sodium in food. The rest would be added in processing, preparation or at the table. Those with kidney, liver or heart problems may have to limit dietary salt, if their doctor advises. But even the very vocal "low salt" exponent, Dr. Arthur Hull Hayes, Jr. admits that "we do not know whether increased sodium consumption causes hypertension." In fact, there is growing scientific evidence that other factors may be involved: deficiencies in calcium, potassium, perhaps magnesium; obesity (much more dangerous than sodium); genetic predisposition; stress. "It is not your enemy," says Dr. Laragh. "Salt is the No. 1 natural component of all human tissue, and the idea that you don't need it is wrong. Unless your doctor has proven that you have a salt-related health problem, there is no mason to give it up.

单选题A wind tunnel can be used to find out ______.

单选题Questions 14 to 16 are based on an interview about a police officer talking about her work. You now have 15 seconds to read Questions 14 to 16.

单选题By saying "With Mars the scientific stakes are arguably higher than they have ever been" in the fourth paragraph, the author means that ______.

单选题The Tories were the forerunners of______, which still bears this nickname today. [A] the Labour Party [B] the Conservative Party [C] the Liberal Democrats [D] the Democratic Party

单选题What is essential to equality in the labour market according to feminists?

单选题Why does the author say high consumption is a mixed blessing?

单选题Whatwasthecauseofthetragedy?A.Badweather.B.Humanerror.C.Breakdownoftheengines.D.Communicationssystemfailure.

单选题 Questions 17—20 are based on the following conversation.

单选题Whatisthemainproblemcausedbytheusualwayofplowing?A.Thecrop'sbloomingperiodisdelayed.B.Therootsofcropsarecutoff.C.Thetopsoilisseriouslydamaged.D.Thegrowthofweedsisaccelerated.

单选题Questions 4～6 are based on the following talk; listen and choose the best answer.

单选题Visitors to St Paul''s Cathedral are sometimes astonished as they walk round the space under the dome to come upon a statue which would appear to be that of a retired gladiator meditating upon a wasted life. They are still more astonished when they see under it an inscription indicating that it represents the English writer, Samuel Johnson. The statue is by Bacon, but it is not one of his best works. The figure is, as often in 18th-century sculpture, clothed only in a loose robe which leaves arms, legs and one shoulder bare. But the strangeness for us is not one of costume only. If we know anything of Johnson, we know that he was constantly ill all through his life; and whether we know anything of him or not we are apt to think of a literary man as a delicate, weak, nervous sort of person. Nothing can be further from that than the muscular statue. And in this matter the statue is perfectly right. And the fact which it reports is far from being unimportant. "The body and the mind are inextricably interwoven" in all of us, and certainly on Johnson''s case the influence of the body was obvious and conspicuous. His melancholy, his constantly repeated conviction of the general unhappiness of human life, was certainly the result of his constitutional infirmities. On the other hand, his courage, and his entire indifference to pain, were partly due to his great bodily strength. Perhaps the vein of rudeness, almost of fierceness, which sometimes showed itself in his conversation, was the natural temper of an invalid and suffering giant. That at any rate is what he was. He was the victim from childhood of a disease which resembled St Vitus''s Dance. He never knew the natural joy of a free and vigorous use of his limbs; when he walked it was like the struggling walk of one in irons. All accounts agree that his strange gesticulations and contortations were painful for his friends to witness and attracted crowds of starers in the streets. But Reynolds says that he could sit still for his portrait to be taken, and that when his mind was engaged by a conversation the convulsions ceased. In any case, it is certain that neither this perpetual misery, nor his constant fear of losing his reason, nor his many grave attacks of illness, ever induced him to surrender the privileges that belonged to his physical strength. He justly thought no character so disagreeable as that of a chronic invalid, and was determined not to be one himself. He had known what it was to live on four pence a day and scorned the life of sofa cushions and tea into which well-attended old gentlemen so easily slip.

单选题Whatis"busbunching"?A.Thephenominonthatanumberofbusesarriveatastopsimultaneously.B.Thephenominonthatanumberofbusesaredelayedatthesametime.C.Thephenominonthatanumberofbusesarerunningonthesamestreetatthesametime.D.Thesituationthatabushasmorethantheusualnumberofpassengersonboard.

单选题The destruction of our natural resources and contamination of our food supply continue to occur, largely because of the extreme difficulty in affixing legal responsibility on those who continue to treat our environment with reckless abandon. Attempts to prevent pollution by legislation, economic incentives and friendly persuasion have been met by lawsuits, personal and industrial denial and long delays -- not only in accepting responsibility, but more importantly, in doing something about it. It seems that only when the government decides it can afford tax incentives or production sacrifices is there any initiative for change. Where is industry's and our recognition that protecting mankind's great treasure is the single most important responsibility? If ever there will be time for environmental health professionals to come to the frontlines and provide leadership to solve environmental problems, that time is now. We are being asked, and, in fact, the public is demanding that we take positive action. It is our responsibility as professionals in environmental health to make the difference. Yes, the ecologist, the environmental activists and the conservationists serve to communicate, stimulate thinking and promote behavioral change. However, it is those of us who are paid to make the decisions to develop, improve and enforce environmental standards, I submit, who must lead the charge. We must recognize that environmental health issues do not stop at city limits, county lines, state or even federal boundaries. We can no longer afford to be tunnel-visioned in our approach. We must visualize issues from every perspective to make the objective decisions. We must express our views clearly to prevent media distortion and public confusion. I believe we have a three-part mission for the present. First, we must continue to press for improvements in the quality of life that people can make for themselves. Second, we must investigate and understand the link between environment and health. Third, we must be able to communicate technical information in a form that citizens can understand. If we can accomplish these three goals in this decade, maybe we can finally stop environmental degradation, and not merely hold it back. We will then be able to spend pollution dollars truly on prevention rather than on bandages.

单选题Defenders of special protective labor legislation for women often maintain that eliminating such laws would destroy the fruits of a century-long struggle for the protection of women workers. Even a brief examination of the historic practice of courts and employers would show that the fruit of such laws has been bitter; they are, in practice, more of a curse than a blessing. Sex-defined protective laws have often been based on stereotypical assumptions concerning women"s needs and abilities, and employers have frequently used them as legal excuses for discriminating against women. After the Second World War, for example, businesses and government sought to persuade women to vacate jobs in factories, thus making room in the labor force for returning veterans. The revival or passage of state laws limiting the daily or weekly work hours of women conveniently accomplished this. Employers had only to declare that overtime hours were a necessary condition of employment or promotion in their factory, and women could be quite legally fired, refused jobs, or kept at low wage levels, all in the name of "protecting" their health. By validating such laws when they are challenged by lawsuits, the courts have colluded over the years in establishing different, less advantageous employment terms for women than for men, thus reducing women"s competitiveness on the job market. At the same time, even the most well-intentioned lawmakers, courts, and employers have often been blind to the real needs of women. The lawmakers and the courts continue to permit employers to offer employee health insurance plans that cover all known human medical disabilities except those relating to pregnancy and Childbirth. Finally, labor laws protecting only special groups are often ineffective at protecting the workers who are actually in the workplace. Some chemicals, for example, pose reproductive risks for women of childbearing years; manufacturers using the chemicals comply with laws protecting women against these hazards by refusing to hire them. Thus the sex-defined legislation protects the hypothetical female worker, but has no effect whatever on the safety of any actual employee. The health risks to male employees in such industries cannot be negligible, since chemicals toxic enough to cause birth defects in fetuses or sterility in women are presumably harmful to the human metabolism. Protectiy laws aimed at changing production materials or techniques in order to reduce such hazards would benefit all employees without discriminating against any. In sum, protective labor laws for women are discriminatory, and do not meet their intended purpose. Legislators should recognize that women are in the work force to stay, and that their needs—good health care, a decent wage, and a safe workplace—are the needs of all workers. Laws that ignore these facts violate women"s rights for equal protection in employment.

单选题 Questions 14～16 are based on the following talk.

单选题Whatdoesthemanthinkofthegovernment'spresentproposalaboutbuildingmorepowerstationsinthecountry?A.It'sadangerousproposal.B.It'sastupidproposal.C.It'sanadvantageousproposal.D.It'saviableproposal.

单选题{{B}}Text 2{{/B}} Diamonds are best known as the "girl's best friend" in rings, tiaras and the Pink Panther films. Yet the aesthetic uses for these sparklers are in the minority. Today, many diamonds are made synthetically for a vast range of uses, from surgeons' scalpels to super-fast microchips. Labs produce 180 tonnes of diamond each year--almost nine times as much as comes out of the ground. And its strength, clarity and chemical resistance could make it the engineering material of the 21st century. Already, there are diamond heat sinks for tiny integrated circuits, diamond coatings on joint replacements and diamond windows on space probes. Soon, a diamond coating could protect your car gearbox, and super-strong diamond threads be used to reinforce ultra-light aircraft. Diamond is far more than just a pretty rock. It has an impressive list of properties. As the hardest material known to science, it is resistant to attack by strong acids and alkalis and is a superb conductor of heat. This all means that there are many uses for diamond apart from the purely decorative. Because it dissipates heat so well--much better than silicon, engineers want to build microchips on layers of diamond. They could then squeeze yet more electronic components into smaller areas without the circuit overheating, to produce a new generation of super-fast computers. The key to diamond's extraordinary properties is its structure. Carbon can form four strong bonds with other molecules, which is why it forms the basis of so many organic compounds and is the building block of life. When four carbon atoms are linked together in a regular lattice, the result is a diamond crystal. Another form of carbon is the graphite in pencils. Companies such as De Beers and General Electric have been making synthetic diamonds since the early 1950s. Almost any substance rich in carbon can be converted into diamond. General Electric chemist Robert Wentorf once made diamonds from peanut butter. A newer process, chemical vapour deposition(CVD), is used to produce ultra-hard diamond coatings. CVD used high temperatures but low pressures to coat a substance with carbon vapour, as a layer of small diamond crystals. These crystals will eventually join together and can be used to create huge gems. Diamonds such as this are usually sliced up to produce long scalpels or other tools. CVD has scientists excited. "For the first time, we have all the superlative properties of diamond in a form that's useful for engineering applications." Says May, who uses CVD to create diamond threads by coating tungsten wire. So it seems that diamonds are not just a girl's best friend, but an engineer's too.

单选题{{B}}TEXT 2{{/B}} Although we already know a great deal about influenza, and although the World Health Organization is constantly collecting detailed information from its chain of influenza reference laboratories throughout the world, it is extremely difficult for epidemiologists, who study infectious disease, to predict when and where the next flu epidemic will occur, and how severe it will be. There are three kinds of influenza virus, known as A, B and C. Influenza C virus is relatively stable and causes mild infections that do not spread far through the population. The A and B types are unstable, and are responsible for the epidemics that cause frequent concern. Following any virus attack, the human body builds up antibodies which confer immunity to that strain of virus, but a virus with the capacity to change its character is able to by-pass this protection. Variability is less developed in the influenza B virus, which affects only human beings. An influenza B virus may cause a widespread epidemic but will have little effect if introduced into the same community soon afterwards, since nearly everyone will have built up antibodies and will be immune. The influenza A virus, which affects animals also, is extremely unstable and is responsible for some of the worst outbreaks of the disease, such as the unparalleled pandemic, or world epidemic, of 1918-19, when about half the world's population were infected and about twenty million people died, some from pneumonia caused by the virus itself and some from secondary complications caused by bacteria. Accurate prediction is difficult because of the complication of the factors. A particular virus may be related to one to which some of the population have partial involved immunity. The extent to which it will spread will depend on factors such as its own strength, or virulence the ease with which it can be transmitted and the strength of the opposition it encounters. Scientists, however, have a reliable general picture of the world situation, influenza A attacks us in waves every two or three years, while influenza B, which travels more slowly, launches its main assaults every three to six years. The outbreaks vary from isolated cases to epidemic involving a tenth or more of the population. We may confidently prophesy that sooner or later large numbers of people will be feeling the unpleasant effects of some kind of influenza virus.

单选题The idea that government should regulate intellectual property through copyrights and patents is relatively recent in human history, and the precise details of what intellectual property is protected for how long vary across nations and occasionally change. There are two standard sociological justifications for patents or copyrights: They reward creators for their labor, and they encourage greater creativity. Both of these are empirical claims that can be tested scientifically and could be false in some realms. Consider music. Star performers existed before the 20th century, such as Franz Liszt and Niccolo Paganini, but mass media produced a celebrity system promoting a few stars whose music was not necessarily the best or most diverse. Copyright provides protection for distribution companies and for a few celebrities, thereby helping to support the industry as currently defined, but it may actually harm the majority of performers. This is comparable to Anatole France's famous irony, "The law, in its majestic equality, forbids the rich as well as the poor to sleep under bridges." In theory, copyright covers the creations of celebrities and obscurities equally, but only major distribution companies have the resources to defend their property rights in court. In a sense, this is quite fair, because nobody wants to steal unpopular music, but by supporting the property rights of celebrities, copyright strengthens them as a class in contrast to anonymous musicians. Internet music file sharing has become a significant factor in the social lives of children, who download bootleg music tracks for their own use and to give as gifts to friends. If we are to believe one recent poll done by a marketing firm rather than social scientists, 48 of American Internet users aged 12 to 17 had downloaded music files in the past month. In so doing, they violate copyright laws, and criminologists would hypothesize they thereby learn contempt for laws in general. A poll by the Pew Internet and American Life Project found that two-thirds of an estimated 35 million Americans who download music files do not care whether they are copyrighted. Thus, on the level of families, ending copyright could be morally as well as economically advantageous. On a much higher level, however, the culture-exporting nations (notably the United States) could stand to lose, although we cannot really predict the net balance of costs and benefits in the absence of proper research. We do not presently have good cross national data on file sharing or a well-developed theoretical framework to guide research on whether copyright protection supports cultural imperialism versus enhancing the positions of diverse cultures in the global marketplace. It will not be easy to test such hypotheses, and extensive economic research has not conclusively answered the question of whether the patent system really promotes innovation. We will need many careful, sharp-focus studies of well-formed hypotheses in specific industries and sectors of life. For example, observational and interview research can uncover the factors that really promote cultural innovation among artists of various kinds and determine the actual consequences for children of Internet peer-to-peer file sharing.