单选题The study proved that the cause of the sex-ratio problem is

单选题Few insects have inspired as much fear and hatred as the diminutive fire ants, less than half an inch long but living in colonies of more than 250,000 others. Everyone in the southern United States gets to know fire ants sooner or later by painful experience. Fire ants live in large earthen mounds and are true social insects—that means they have a caste system (division of labor), with a specialized caste that lays eggs (queen) and a worker caste of sterile females. There are several reasons that they are considered pests. About 60% of people living in areas where fire ants occur are stung every year. Of these, about 1% have some degree of allergic reaction (called anaphylaxis) to the sting. Their large mounds are unsightly and can damage mowing equipment. Fire ants sometimes enter electrical and mechanical equipment and can short out switches or chew through insulation. Finally, as fire ants move into new areas, they reduce diversity of native ants and prey on larger animals such as ground-nesting birds and turtles. Even though fire ants are pests in many circumstances, they can actually be beneficial in others. There is evidence that their predatory activities can reduce the numbers of some other important pests. In cotton, for example, they prey on important pests that eat cotton plants such as bollworms and budworms. In Louisiana sugarcane, an insect called the sugar-cane borer used to be a very important pest before fire ants arrived and began preying on it. Fire ants also prey on ticks and fleas. Whether fire ants are considered pest or not depend on where they are found, but one thing is sure—we had best get used to living with them. Eradication attempts in the 1960s and 1970s failed for a number of reasons, and scientists generally agree that complete elimination of fire ants from the United States is not possible. A new, long-term approach to reducing fire ant populations involves classical biological control. When fire ants were accidentally brought to the United States, most of their parasites and diseases were not. Classical biological control involves identifying parasites and diseases specific to fire ants in South America, testing them to be sure that they don' t attack or infect native plants or animals, and establishing them in the introduced fire ant population in the United States. Since fire ants are about 5 to 7 times more abundant here than in South America, scientists hope to re-duce their numbers using this approach.

单选题Political controversy about the public-land policy of the United States began with the America Revolution. (1) , even before independence from Britain was (2) , it became clear that (3) the dilemmas surrounding the public domain might prove necessary to (4) the Union itself. At the peace negotiation with Britain, Americans obtained a western (5) at the Mississippi River. Thus the new nation secured for its birthright a vast internal empire rich in agricultural and mineral resources. But (6) their colonial charters, seven states claimed (7) of the western wilderness. Virginia's claim was the largest, (8) north and west to encompass the later states. The language of the charters was (9) and their validity questionable, but during the war Virginia reinforced its title by sponsoring Colonel Georgia Rogers Clark's 1778 (10) to Vicennes and Kaskaskia, which (11) America's trans Appalachian pretensions at the peace table. The six states holding no claim to the transmontane region (12) whether a confederacy in which territory was so unevenly apportioned would truly prove what it claimed to be, a union of equals. Already New Jersey, Delaware, Rhode Isaland, and Maryland were (13) the smallest and least populous of the states. (14) they levied heavy taxes to repay state war debts, their larger neighbors might retire debts out of land-sale proceeds. (15) by fresh lands and low taxes, people would desert the small states (16) the large, leaving the former to fall (17) bankruptcy and eventually into political subjugation. All the states shared in the war effort, how then could half of them "be left no sink under an (18) debt, whilst others are enabled, in a short period, to (19) all their expenditures from the hard earnings of the whole confederacy?" As the Revolution was a common endeavor, (20) ought its fruits, including the western lands be a common property.

单选题{{B}}Text 4{{/B}} Machines and foreign competition will replace millions of American jobs. But work will be plentiful for people trained in the occupations of the future. The Labor Department predicts a net increase of 25 million new jobs in the United States in 1995 with service-industry jobs growing three times as rapidly as factory jobs. "Work will shift its emphasis from the fatigue and monotony of the production line and the typing pool to the more interesting challenge of the electronic service center, the design studio, the research laboratory, the education institute and the training school," predicts Canadian economist Calvert. Jobs in high-tech fields will multiply fastest, but from a low base. In terms of actual numbers, more mundane occupations will experience the biggest surge: custodians, cashiers, secretaries, waiters and clerks. Yet much of the drudge work will be taken on by robots. The number of robots performing blue-collar tasks will increase from 3,000 in 1981 to 40,000 in 1990, says John E. Taylor of the Human Resources Research Organization in Alexandria, Va. Robots might also be found on war zones, in space- even in the office, perhaps making coffee, opening mail and delivering messages. One unsolved problem, what to do with workers displaced by high technology and foreign competition. Around the world "the likelihood of growing permanent unemployment is becoming more accepted as a reality among social planners," notes David Macarov, associate professor of the Hebrew University in Jerusalem. Meantime at the percentage of time people spend on the job is likely to continue to fall. Robert Theobald, author of Avoiding in 1984, fears that joblessness will lead to increasing depression, bitterness and unrest. "The dramatic consequences of such a shift on the Western psyche, which has made the job the way we value human beings, are almost incalculable," he comments. Because of the constantly changing demand for job skills, Ron Kutschner, associate commissioner of the Bureau of Labor Statistics, offers this advice for today' s high school students: "Be prepared with a broad education, like the kind pre-college students get--basic math. science and English. Prepare yourself to handle each new technology, as it comes down the road. Then get technology training for your first job. That is the best stepping stone to the second and third jobs."

单选题Stanley won the race most probably because

单选题To learn lessons from Nature, the author advocates that humans should______.

单选题{{B}}Text 3{{/B}} That Louise Nevelson is believed by many critics to be the greatest twentieth-century sculptor is all the more remarkable because the greatest resistance to women artists has been, until recently, in the field of sculpture. Since Neolithic times, sculpture has been considered the prerogative of men, partly, perhaps, for purely physical reasons: it was erroneously assumed that women were not suited for the hard manual labor required in sculpting stone, carving wood, or working in metal. It has been only during the twentieth century that women sculptors have been recognized as major artists, and it has been in the United States, especially since the decades of the fifties and sixties, that women sculptors have shown the greatest originality and creative power. Their rise to prominence parallels the development of sculpture itself in the United States: while there had been a few talented sculptors in the United States before the 1940’s, it was only after 1945 — when New York was rapidly becoming the art capital of the world — that major sculpture was produced in the United States. Some of the best was the work of women. By far the most outstanding of these women is Louise Nevelson, who in the eyes of many critics is the most original female artist alive today. One famous and influential critic, Hilton Kramer, said of her work, “For myself, I think Ms. Nevelson succeeds where the painters often fail.” Her works have been compared to the Cubist constructions of Picasso, the Surrealistic objects of Miro, and the Merzbau of Schwitters. Nevelson would be the first to admit that she has been influenced by all of these, as well as by African sculpture, and by Native American and pre-Columbian art, but she has absorbed all these influences and still created a distinctive art that expresses the urban landscape and the aesthetic sensibility of the twentieth century. Nevelson says, “I have always wanted to show the world that art is everywhere, except that it has to pass through a creative mind.” Using mostly discarded wooden objects like packing crates, broken pieces of furniture, and abandoned architectural ornaments, all of which she has hoarded for years, she assembles architectural constructions of great beauty and power. Creating very freely with no sketches, she glues and nails objects together, paints them black, or more rarely white or gold, and places them in boxes. These assemblages, walls, even entire environments create a mysterious, almost awe-inspiring atmosphere. Although she has denied any symbolic or religious intent in her works, their three-dimensional grandeur and even their titles, such as Sky Cathedral and Night Cathedral, suggest such connotations. In some ways, her most ambitious works are closer to architecture than to traditional sculpture, but then neither Louise Nevelson nor her art fits into any neat category.

单选题Confucius is cited by the author in the first paragraph to imply that

单选题Homework has never been terribly popular with students and even many parents, but in recently years it has been particularly scorned. School districts across the country, most recently Los Angeles Unified, are revising their thinking on this educational ritual. Unfortunately, L.A. Unified has produced an inflexible policy which mandates that with the exception of some advanced courses, homework may no longer count for more than 10% of a student"s academic grade. This rule is meant to address the difficulty that students from impoverished or chaotic homes might have in completing their homework. But the policy is unclear and contradictory. Certainly, no homework should be assigned that students cannot complete on their own or that they cannot do without expensive equipment. But if the district is essentially giving a pass to students who do not do their homework because of complicated family lives, it is going riskily close to the implication that standards need to be lowered for poor children. District administrators say that homework will still be a part of schooling; teachers are allowed to as-sign as much of it as they want. But with homework counting for no more than 10% of their grades, students can easily skip half their homework and see very little difference on their report cards. Some students might do well on state tests without completing their homework, but what about the students who performed well on the tests and did their homework? It is quite possible that the homework helped. Yet rather than empowering teachers to find what works best for their students, the policy imposes a flat, across-the-board rule. At the same time, the policy addresses none of the truly thorny questions about homework. If the district finds homework to be unimportant to its students" academic achievement, it should move to reduce or eliminate the assignments, not make them count for almost nothing. Conversely, if homework matters, it should account for a significant portion of the grade. Meanwhile, this policy does nothing to ensure that the homework students receive is meaningful or appropriate to their age and the subject, or that teachers are not assigning more than they are willing to review and correct. The homework rules should be put on hold while the school board, which is responsible for setting educational policy, looks into the matter and conducts public hearings. It is not too late for L.A. Unified to do homework right.

单选题Michael Porter, who has made his name throughout the business community by advocating his theories of competitive advantages, is now swimming into even more shark-infested waters, arguing that competition can save even America's troubled health-care system, the largest in the world. Mr. Porter argues in "Redefining Health Care" that competition, if properly applied, can also fix what ails this sector. That is a bold claim, given the horrible state of America's health-care system. Just consider a few of its failings: America pays more per capita for health care than most countries, but it still has some 45m citizens with no health insurance at all. While a few receive outstanding treatment, he shows in heart-wrenching detail that most do not. The system, wastes huge resources on paperwork, ignores preventive care and, above all, has perverse incentives that encourage shifting costs rather than cutting them outright. He concludes that it is "on a dangerous path, with a toxic combination of high costs, uneven quality, frequent errors and limited access to care." Many observers would agree with this diagnosis, but many would undoubtedly disagree with this advocacy of more market forces. Doctors have an intuitive distrust of competition, which they often equate with greed, while many public-policy thinkers argue that the only way to fix America's problem is to quash the private sector's role altogether and instead set up a government monopoly like Britain's National Health Service. Mr. Porter strongly disagrees. He starts by acknowledging that competition, as it has been introduced to America's health system, has in fact done more harm than good. But he argues that competition has been introduced piecemeal, in incoherent and counter-productive ways that lead to perverse incentives and worse outcomes:" health-care competition is not focused on delivering value for patients," he says. Mr. Porter offers a mix of solutions to fix this mess, and thereby to put the sector on a genuinely competitive footing. First comes the seemingly obvious (but as yet unrealized) goal of data transparency. Second is a redirection of competition from the level of health plans, doctors, clinics and hospitals, to competition "at the level of medical conditions, which is all but absent". The authors argue that the right measure of "value" for the health sector should be how well a patient with a given health condition fares over the entire cycle of treatment, and what the cost is for that entire cycle. That rightly emphasizes the role of early detection and preventive care over techno-fixes, pricey pills and the other fallings of today's system. If there is a failing in this argument, it is that he sometimes strays toward naive optimism. Mr. Porter argues, for example, that his solutions are so commonsensical that private actors in the health system could forge ahead with them profitably without waiting for the government to fix its policy mistakes. That is a tempting notion, but it falls into a trap that economists call the fallacy of the $20 bill on the street. If there really were easy money on the pavement, goes the argument, surely previous passers-by would have bent over and picked it up by now. In the same vein, if Mr. Porter's prescriptions are so sensible that companies can make money even now in the absence of government policy changes, why in the world have they not done so already? One reason may be that they can make more money in the current sub-optimal equilibrium than in a perfectly competitive market—which is why government action is probably needed to sweep aside the many obstacles in the way of Mr. Porter's powerful vision.

单选题All Sumerian cities recognized a number of gods in common, including the sky god, the lord of storms, and the morning and evening star. (1) the Sumerian worshipped the goddess of fertility, love, and war, she was evidently lower (2) status than the male gods, indicating that in a more urbanized society the (3) that the peoples of previous times had paid to the earth mother goddess had (4) . The gods seemed hopelessly violent and (5) , and one's life a period of slavery at their easy will. The epic poem The Creation emphasizes that (6) were created to enable the gods to (7) up working. Each city moreover had its own god, who was considered to (8) the temple literally and who was in theory the owner of all property within the city. (9) the priests who interpreted the will of the god and controlled the (10) of the economic produce of the city were favored (11) their supernatural and material functions (12) . When, after 3,000 B.C., growing warfare among the cities made military leadership (13) , the head of the army who became king assumed a(n) (14) position between the god, whose agent he was, and the priestly class, whom he had both to use and to (15) . Thus king and priests represented the upper class in a hierarchical society. (16) them were the scribes, the secular attendants of the temple, who (17) every aspect of the city's economic life and who developed a rough judicial system. (18) the temple officials, society was divided among an elite or (19) group of large landowners and military leaders; a mixed group of merchants, artisans, and craftsmen, free peasants who (20) the majority of the population; and slaves.

单选题According to the passage, the smart highway technology is aimed to______

单选题The attitude of those who are "barking up the wrong tree" towards the primacy of US in the 21st century seems to be

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 aims 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LAST month, America's National Law Journal told its readers that " employment lawyers are warning lovestruck co-workers to take precautions in the office before locking lips outside". The advice came too late for Harry Stonecipher. The boss of Boeing was forced to resign last weekend--for reasons that will strike many outsiders as absurd--after his board were told of an affair that the 68-year-old married man had been conducting with a female employee "who did not report directly to him". Inevitably, as the week rolled on, details of the affair rolled out. The other party was reported to be Debra Peabody, who is unmarried and has worked for Boeing for 25 years. The couple were said to have first got together at Boeing's annual retreat at Palm Desert, California in January. After that much of the affair must have been conducted from a distance: Mr. Stonecipher's office is at Boeing's headquarters in Chicago; Ms Peabody runs the firm's government-relations office in Washington, DC. They exchanged e-mails, it seems, as office lovers tend to do these days, and therein probably lay Mr Stonecipher's downfall. Lewis Platt, Boeing's chairman, said that Mr Stonecipher broke a company rule that says: "Employees will not engage in conduct or activity that may raise questions as to the company's honesty, impartiality, reputation or otherwise cause embarrassment to the company. " Having an affair with a fellow employee is not, of itself, against company rules; causing embarrassment to Boeing is. It seems that the board judged that the contents of the lovers' e-mails would have been bad for Boeing had they been made public. Gone are the days when a board considered such matters none of its business, as Citibank's did in 1991 when its boss, John Reed, became the talk of Wall Street for having an affair with a stewardess on Citi's corporate jet. At Boeing, a whistleblower is said to have forwarded the messages to Mr Platt. In general, e-mails are encrypted and not accessible to anyone who does not know the sender's password. But many firms install software designed to search electronic communications for key words such as, " sex" and " CEO". A study last year of 840 American firms by the American Management Association found that 60% of them check external e-mails ( incoming and outgoing), while 27% scrutinize internal messages between employees. Sweet nothings whispered by the water cooler may travel less far these days than electronic billets doux. Boeing is particularly sensitive to embarrassment at the moment. Mr. Stonecipher was recalled from retirement only 15 months ago, after the company's previous boss, Phil Condit, and its chief financial officer, Michael Sears, had left in the wake of a scandal involving an illegal job offer to a Pentagon official. Mr Stonecipher, a crusty former number two at Boeing, was brought back specifically to raise the company's ethical standards and to help it be seen in its main (and affectedly puritanical) market, in Washington, DC, as squeaky clean. Verbally explicit extra-marital affairs are inconsistent with such a strategy, it seems, though they are not yet enough to bring down future kings of England. In corporate life, such affairs are hardly unusual. One survey found that one-quarter of all long-term relationships start at work; another found that over 40% of executives say they have been involved in an affair with a colleague, and that in half of these cases one or other party was married at the time. Many a boss has married his assistant and lived happily ever after. Boeing apparently used to accept this: Mr. Condit's fourth wife was a colleague before they married.

单选题Which of the following was NOT mentioned as part of the "new factory system" ?______

单选题As you try to imagine yourself cruising along in the self-driving car of the future, you may think first of the technical challenges. But the more difficult challenges may have to do with ethics. Recent advances in artificial intelligence are enabling the creation of systems capable of independently pursuing goals in complex, real-world settings—often among and around people. Serf-driving cars are merely the vanguard of an approaching fleet of equally autonomous devices. As these systems increasingly invade human domains, the need to control what they are permitted to do, and on whose behalf, will become more acute. Within the next few decades, our stores, streets and sidewalks will likely be crammed with robotic devices fetching and delivering goods of every variety. How do we ensure that they respect the unstated conventions that people unconsciously follow when navigating in crowds? A debate may erupt over whether we should share our turf with machines or banish them to separate facilities. Will it be "Integrate Our Androids!" or "Ban the Bots!" And far more serious issues are on the horizon. Should it be permissible for an autonomous military robot to select its own targets? The current consensus in the international community is that such weapons should be under "meaningful human control" at all times, but even this seemingly sensible constraint is ethically muddled. The expanded use of such robots may reduce military and civilian casualties and avoid collateral damage. So how many people"s lives should be put at risk waiting for a human to review a robot"s time-critical kill decision? Even if we can codify our principles and beliefs algorithmically, that won"t solve the problem. Simply programming intelligent systems to obey rules isn"t sufficient, because sometimes the right thing to do is to break those rules. Blindly obeying a posted speed limit of 55 miles an hour may be quite dangerous, for instance, if traffic is averaging 75, and you wouldn"t want your self-driving car to strike a pedestrian rather than cross a double-yellow centerline. People naturally abide by social conventions that may be difficult for machines to perceive, much less follow. Finding the right balance between our personal interests and the needs of others—or society in general-is a finely calibrated human instinct, driven by a sense of fairness, reciprocity and common interest. Today"s engineers, racing to bring these remarkable devices to market, are ill-prepared to design social intelligence into a machine. Their real challenge is to create civilized robots for a human world.