单选题He ______ that he has discovered a new planet.

单选题From the last paragraph the conclusion can be drawn that scientists______.

单选题General George Washington and his hungry, ragged troops crossed the Delaware River from Pennsylvania, surprised the garrison of German mercenaries in Trenton, and captured the city. A. provocative B. foppish C. formidable D. shabby

单选题He was ______ with the deadly disease when he was 14, and has suffered with it for 10 years. A. induced B. inflicted C. inserted D. integrated

单选题Protection of the environment is based on a principle that is beginning to be used in the field of jurisprudence. The principle has to do with property rights. The idea is that we all have a property right in the air and water around us. If a business firm pollutes that air or water, their act in so doing constitutes damage to something we own—just as if the firm had dropped a smoke bomb down our chimney. Our legal ease against such a firm is then baaed on the complaint that we deserve compensation for an infringement of our right to use our private property as we please ( provided we don' t interfere with the same rights of a neighbor). Assuming we win the case, the offending firm then has to pay us for damaging our property—the air or water we "own". And so protection of the environment, specifically the control of pollution, now rests on the idea that we, as members of the public, share a right to clean air and water and to the good health that clean air and water quality can give us. But, as always, costs and benefits are involved in any decision to improve the environment. In an Adam Smithian, self-interested world, entrepreneurs or businessmen are expected to increase their profits as much as possible. The natural way to do this is to produce at the lowest possible cost. But at whose cost? It is obviously cheaper for entrepreneurs to dump waste into the nearest stream or into the atmosphere than to truck it to some waste disposal facility or to filter it as it comes out of smokestacks. Therefore, what may be sensible for entrepreneurs may not be desirable for the community. Here is a classic trade-off: When the government intervenes to force entrepreneurs to stop polluting, entrepreneurs have to adopt more expensive means of production or waste disposal. Inevitably, they will charge higher prices, and, given no change in demand, the quantity demanded will drop and workers will be laid off. The trade-off is therefore cleaner air and water or more unemployment. This is how economists view this problem.

单选题Climatic conditions are delicately adjusted to the composition of the Earth's atmosphere. If there were a change in the atmosphere for example, in the relative proportions of atmosphere gases the climate would probably change also. A slight increase in water vapor, for instance, would increase the heat-retaining capacity of the atmosphere and would lead to a rise in global temperatures. In contrast, a large increase in water vapor would increase the thickness and extent of the cloud layer, reducing the amount of solar energy reaching the Earth's surface. The level of carbon dioxide, CO2, in the atmosphere has an important effect on climatic change. Most of the Earth's incoming energy is short wavelength radiation, which tends to pass through atmospheric CO2 easily. The Earth, however, reradiates much of the received energy as a long wavelength radiation, which CO2 absorbs and then remits toward the Earth. This phenomenon, known as the greenhouse effect, can result in an increase in the surface temperature of a planet. An extreme example of the effect is shown by the Venus, a planet covered by heavy clouds composed mostly of CO2, whose surface temperatures have been measured at 430℃. If the CO2 content of the atmosphere is reduced, the temperature falls. According to one respectable theory, if the atmospheric CO2 concentration were halved, the Earth would become completely covered with ice. Another equally respectable theory, however, states that a halving of the CO2 concentration would lead only to a reduction in global temperatures of 3℃. If, because of an increase in forest fires or volcanic activities, the CO2 content of the atmosphere increased, a warmer climate would be produced. Plant growth, which relies on both the warmth and the availability of CO2, would probably increase. As a consequence, plants would use more and more CO2. Eventually CO2 levels would diminish and the climate, in turn, would become cooler. With reduced temperatures many plants would die; CO2 would thereby be returned to the atmosphere and gradually the temperatures would rise again. Thus, if this process occurred, there might be a long-term oscillation in the amount of CO2 present in the atmosphere, with regular temperature increases and decreases of a set magnitude. Some climatologists argue that the burning of fossil fuels has raised the level of CO2 in the atmosphere and has caused a global temperature rise of at least 1℃. But a supposed global temperature rise of 1℃ may in reality be only several regional temperature increases, restricted to areas where there are many meteorological stations and caused simply by shifts in the pattern of atmospheric circulation. Other areas, for example, the Southern Hemisphere oceanic zone, may be experiencing an equivalent temperature decrease that is unrecognized because of the shortage of meteorological recording stations.

单选题In his ______ to further knowledge of the universe, man has now begun to explore space.(2003年南京大学考博试题)

单选题 Human beings are animals. We breathe, cat end digest, and reproduce-the same life{{U}} (71) {{/U}}common to all animals. In a biological laboratory, rats, monkeys, and humans seem very much the same. However, biological understanding is not enough:{{U}} (72) {{/U}}itself, it can never tell us what human beings are. {{U}}(73) {{/U}}to our physical equipment—the naked human body—we are not an{{U}} (74) {{/U}}animal. We are tropical creatures, {{U}}(75) {{/U}}hairless and sensitive to cold. We are not fast and have neither claws nor sharp teeth to defend ourselves. We need a lot of food but have almost no physical equipment to help us get it. In the purely physical{{U}} (76) {{/U}}, our species seems a poor{{U}} (77) {{/U}}for survival. But we have survived—survived and multiplied and{{U}} (78) {{/U}}the earth. Some day we will have a{{U}} (79) {{/U}}living on the moon, a place with neither air nor water and with temperatures that turn gases into solids. How can we have done all these things? Part of the answer is physical. {{U}}(80) {{/U}}its limitations, our physical equipment has some important{{U}} (81) {{/U}}. We have excellent vision and hands that can{{U}} (82) {{/U}}objects with a precision unmatched by any other{{U}} (83) {{/U}}. Most importantly, we have a large brain with an almost{{U}} (84) {{/U}}number of neural{{U}} (85) {{/U}}. We have used this physical equipment to create culture, the key to our survival and success. If we live in the Arctic. we supply the warmth our tropical bodies need{{U}} (86) {{/U}}clothing, shelter, and{{U}} (87) {{/U}}heat. If a million people want to live in a desert that supplies natural food for only a few hundred, we find water to grow food and{{U}} (88) {{/U}}deficits by transporting supplies from distant places. Inhabitants of our eventual moon colony will bring their own food and oxygen and then create an artificial earth environment to supply necessities. With culture, we can overcome our natural limitations. It was not always{{U}} (89) {{/U}}. 0ur distant ancestors were just animals, faced with the limits of their physical equipment. They had no{{U}} (90) {{/U}}and lacked the physical capacity to use it.

单选题Ask an American schoolchild what he or she is learning in school these days and you might even get a reply, provided you ask it in Spanish. But don't bother, here's the answer. Americans nowadays are not learning any of the things that we learned in our day, like reading and writing. Apparently these are considered fusty old subjects, invented by white males to oppress women and minorities. What are they learning? In a Vermont college town I found the answer sitting in a toy store book rack, next to typical kids' books like "Heather Has Two Mommies and Daddy is 'Dysfunctional'". It's a teacher's guide called "Happy To Be Me", subtitled "Building Self-Esteem". Self-esteem as it turns out, is a big subject in American classrooms. Many American schools see building it as important as teaching reading and writing. They call it "whole language" teaching, borrowing terminology from the granola people to compete in the education marketplace. No one ever spent a moment building my self-esteem when I was in school. In fact, from the day I first stepped inside a classroom my self-esteem was one big demolition site. All that mattered was "the subject", be it geography, history, or mathematics. I was praised when I remembered that "near", "fit", "friendly", "pleasing", "like" and their opposites took the dative case in Latin. I was reviled when I forgot what a cosine was good for. Generally, I lived my school years beneath a torrent of castigation so consistent I eventually ceased to hear it, as people who live near the sea eventually stop hearing the waves. Schools have changed. Reviling is out, for one thing. More important, subjects have changed. Whereas I learned English, modern kids learn something called "language skills". Whereas I learned writing, modern kids learn something called "communication". Communication, the book tells us, is seven per cent words, twenty three per cent facial expression, twenty per cent tone of voice, and fifty per cent body language. So this column, with its carefully chosen words, would earn at most a grade of seven per cent. That is, if the school even gave out something as oppressive and demanding as grades. The result is that, in place of English classes, American children are getting a course in "How to Win Friends and Influence People". Consider the new attitude toward journal writing: I remember one high school English class when we were required to keep a journal. The idea was to emulate those great writers who confided in dimes, searching their soul and honing their critical thinking on paper. "Happy To Be Me" states that journals are a great way for students to get in touch with their feelings. Tell students they can write one sentence or a whole page. Reassure them that no one, not even you, will read what they write. After the unit, hopefully all students will be feeling good about themselves and will want to share some of their entries with the class. There was a time when no self-respecting book for English teachers would use "great" or "hopefully" that way. Moreover, back then the purpose of English courses (an antique term for "Unit") was not to help students "feel good about themselves". Which is good, because all that reviling didn't make me feel particularly good about anything .

单选题The purchaser of this lorry is protected by the manufacturer's {{U}}warranty{{/U}} that he will replace any defective part for five years or 50000 miles. A prohibition B. insurance C. prophecy D. guarantee

单选题Children tend to______while playing, even if they make a promise before.

单选题Instead of feeling surrounded by information, first-timers, "newbies" in the______of the Net, are likely to find themselves adrift in a borderless sea.

单选题What does the word "adopt" (par

单选题Advanced mammals such as monkeys, apes and humans have brains ______ from ancestors that took to living in the trees. A. derived B. progressed C. terminated D.advanced

单选题Over-taxation, many argue, impedes initiative, so that government income may actually ______.

单选题Floors and walls must be specially constructed to make a building soundproof.

单选题Human behavior is mostly a product of learning, whereas the behavior of an animal depends mainly on ______(2005年春季电子科技大学考博试题)

单选题The author, as a "middle ground" person, ______.

单选题 To what extent are the unemployed failing in their duty to society to work, and how far has the State an obligation to ensure that they have work to do? It is by now increasingly recognized that workers may be thrown out of work by industrial forces beyond their control, and that the unemployed are in some sense paying the price of the economic progress of the community. But concern with unemployment and the unemployed changes sharply. The issues of duty and responsibility were re-opened and made active by the unemployment scare of 1971--1972. Rising unemployment and increased sums paid out in benefits to the workless had reawakened controversies which had been inactive during most of the period of fuller employment since the war ended the Depression. It looked as though in future there would again be too little work to go round, so there were arguments about how to produce more work, how the available work should be shared out, and who was responsible for unemployment and the unemployed. In 1972 there were critics who said that the State's action in allowing unemployment to rise was a barrier of faith, a breaking of the social contract between society and the worker. Yet the main contribution by employers to unemployment--such as laying off workers in order to introduce technological changes and maximize profit-tended to be ignored. And it was the unemployed who were accused of failing to honor the social contract, by not fulfilling their duty to society to work. In spite of general concern at the scale of the unemployment statistics when the unemployed were considered as individuals they tended to attract scorn and threats of punishment. Their capacities and motivation as workers and their values as members of society became suspect. Of all the myths of the Welfare State, stories of the workshy and stealing have been the least well founded on evidence, yet they have proved the most persistent. The unemployed were accused of being responsible for their own workless condition, and doubts were expressed about the State's obligation either to provide them with the security of work or to support them through social security. Underlying the arguments about unemployment and the unemployed is a basic disagreement about the nature and meaning of work in society. To what extent can or should work be regarded as a service, not only performed by the worker for society but also made secure for the worker by the State, and subsidized if necessary? And apart from cash are there social pressures and satisfactions which cause individuals to seek and keep work, so that the workless need work rather than just cash?