单选题American society is not nap(午睡)friendly. In fact, says David Dinges, a sleep specialist at the University of Pennsylvania School of Medicine. "There's even a prohibition against admitting we need sleep. " Nobody wants to be caught napping or found asleep at work. To quote a proverb: "Some sleep five hours, nature requires seven, laziness nine and wickedness eleven. " Wrong. The way not to fall asleep at work is to take naps when you need them. "We have to totally change our attitude toward napping," says Dr. William Dement of Stanford University, the godfather of sleep research. Last year a national commission led by Dement identified an "American sleep debt" which one member said was as important as the national debt. The commission was concerned about the dangers of sleepiness: people causing industrial accidents or falling asleep while driving. This may be why we have a new sleep policy in the White House. According to recent reports, president Clinton is trying to take a half hour snooze(打瞌睡)every afternoon. About 60 percent of American adults nap when given the opportunity. We seem to have "a midafternoon quiet phase" also called "a secondary sleep gate. " Sleeping 15 minutes to two hours in the early afternoon can reduce stress and make us refreshed. Clearly, we were born to nap. We Superstars of Snooze don't nap to replace lost shut eye or to prepare for a night shift. Rather, we "snack" on sleep, whenever, wherever and at whatever time we feel like it. I myself have napped in buses, cars, planes and on boats; on floors and beds; and in libraries, offices and museums.

单选题As the ship is loaded, it will sink deeper and deeper into the water, but only sink deep enough to______an amount of water equal to the weight of the ship and its cargo.(厦门大学2012年试题)

单选题The paint on the clown's face ______ that it scared the children he was trying to entertain.

单选题Less than 40 years ago in the United States, it was common to change a one-dollar bill for a dollar's worth of silver. That is because the coins were actually made of silver. But those days are gone. There is no silver in today's coins. When the price of the precious metal rises above its face value as money, the metal will become more valuable in other uses. Silver coins are no longer in circulation because the silver in coins is worth much more than their face value. A silver firm could find that it is cheaper to obtain silver by melting down coins than by buying it on the commodity markets. Coins today are made of an alloy of cheaper metals. Gresham's Law, named after Sir Thomas Gresham, argues that "good money" is driven out of circulation by "bad money". Good money differs from bad money because it has higher commodity value. Gresham lived in the 16th century in England where it was common for gold and silver coins to be debased. Governments did this by mixing cheaper metals with gold and silver. The governments could thus make a profit in coinage by issuing coins that had less precious metal than the face value indicated. Because different mixings of coins had different amounts of gold and silver, even though they bore the same face value, some coins were worth more than others as commodities. People who dealt with gold and silver could easily see the difference between the "good" and the "bad" money. Gresham observed that coins with a higher content of gold and silver were kept rather than being used in exchange, or were melted down for their precious metal. In the mid-1960s when the U.S. issued new coins to replace silver coins, Gresham's law went right in action.

单选题 Science is a dominant theme in our culture. Since it touches almost every facet of our life, educated people need at least some acquaintance with its structure and operation. They should also have an understanding of the subculture in which scientists live and the kinds of people they are. An understanding of general characteristics of science as well as specific scientific concepts is easier to attain if one knows something about the things that excite and frustrate the scientist. This book is written for the intelligent student or lay person whose acquaintance with science is superficial, for the person who has been presented with science as a musty storehouse of dried facts, for the person who sees the chief objective of science as the production of gadgets, and for the person who views the scientists as some sort of magician. The book can be used to supplement a course in any science, to accompany any course that attempts to give an understanding of the modern work, or--independently of any course --simply to provide a better understanding of science. We hope this book will lead readers to a broader perspective on scientific attitudes and a more realistic view of what science is, who scientists are, and what they do. It will give them an awareness and understanding of the relationship between science and our culture and an appreciation of the roles science may play in our culture. In addition, readers may learn to appreciate the relationship between scientific views and some of the values and philosophies that are pervasive in our culture. We have tried to present in this book an accurate and up-to-date picture of the scientific community and the people who populate it. That population has in recent years come to comprise more and more women. This increasing role of women in the scientific subculture is not a unique incident but, rather, part of the trend evident in all segments of society as more women enter traditionally male-dominated fields and make significant contributions. In discussing these changes and contribution, however, we are faced with a language that is implicitly sexist, one that uses male nouns or pronouns in referring to unspecified individuals. To offset this built-in bias, we have adopted the policy of using plural nouns and pronouns whenever possible and, when absolutely necessary, alternating he and she. This policy is far from being ideal, but it is at least an acknowledgment of the inadequacy of our language in treating half of the human race equally. We have also tried to make the book entertaining as well as informative. Our approach is usually informal. We feel, as do many other scientists, that we shouldn't take ourselves too seriously. As the reader may observe, we see science as a delightful pastime rather than as a grim and dreary way to earn a living.

单选题The sound of the roaring of a tiger is ______ heard by jungle dwellers feelings unease, for a year does not elapse ______ victims falling to the tiger's ferocity.

单选题5 Most people who develop Lyme disease, a tick-born infection that's endemic in parts of the Northeast and Midwest, are easily cured by taking an antibiotic like doxycycline for a couple of weeks. But for years a debate has raged over what to do about patients whose symptoms (fatigue, mental confusion, joint pain) never seem to clear up. One small but vocal group of doctors and patient advocates believes that Lyme's corkscrew-shaped spiro chetes have tunneled deep into their victims' bodies and can be eradicated only with inten sive antibiotic treatment over many months. Another group believes, just as adamantly, that the bacteria are long gone, making further treatment with powerful antibiotics which can lead to potentially fatal infections or blood clots--positively dangerous. Now comes word of two studies in the New England Journal of Medicine that show that long-term antibiotic treatment is no better than a placebo for folks with chronic Lyme disease. Originally scheduled for publication in July, the research is part of a group of find ings made public last week—just in time for the peak Lyme months of June and July. If con firmed by another major study that's looking at chronic Lyme and antibiotics from a slight ly different perspective, the results would seem to settle the question once and for all. Researchers from Boston, New Haven, Conn., and Valhalla, N.Y., followed 129 patients who had previously been treated for well-documented cases of Lyme disease. Sixty four were given antibiotics directly into their veins for a month, followed by two months of oral antibiotics. The others received dummy medications. A third of the chronic Lyme pa tients got better while taking the antibiotics. But so did a third of those on the placebo. Indeed, the results were so similar that a monitoring board decided to cut the trials short rather than add more subjects to the test groups. Unfortunately, the debate over chronic Lyme has become so heated that no one ex pects the controversy to go away. But both sides may take comfort in the other findings that were released by the New England Journal last week. After studying 482 subjects bit ten by deer ticks in a part of New York with a lot of Lyme disease, researchers concluded that a singly 200-mg dose of doxycycline dramatically cut the risk of contracting the dis ease. That good news is tempered somewhat by the fact that 80% of patients who develop the infection don't remember ever being bitten by a tick. (The bugs inject an anesthetic in to the skin to mask the pain and in their nymph stage are so small—about the size of a pop- py seed--that they are easily overlooked. ) There's still plenty you can do to protect yourself in a Lyme-infested neighborhood: tuck your pants in your socks, spray DEET on your clothing, check yourself and your kids for ticks. And if you develop a spreading red rash—particularly if it's accompanied by joint pain, chills or confusion make sure you see a doctor right away. The trick, as al ways, is to be vigilant without overreacting.

单选题______is the question of using existing resources to produce original and benefi cial solutions, ideas or products. A. Creativity B. Productivity C. Application D. Combination

单选题Her taste runs also to arrangements of Chopin and Joplin, as well as to Japanese and Brazilian music, part of______ approach that is winning her fans around the world.

单选题What he said in the meeting______everybody present.

单选题One of the most provocative ideas of modern physics was initiated by the British theorist P. Dirao.

单选题From historical point of view, high heels ______.

单选题A noisy aggressive cousin of the crow, the magpie has those bird's thievish habits.A.A noisy B.aggressive C.those D.habits

单选题Moving pictures present ______ scenes like battles, processions, storms, or races.

单选题According to Nobel's famous will, the interest on his fund will be ______ to five people who have made great contributions to mankind during the previous year.

单选题Although her mind was in a ______, she tried to stay calm for the sake of her children.

单选题These machines have raised______ many times.

单选题Don't Umeddle/U in my affairs, and in fact a I can handle them properly by myself.

单选题Helicopters rushed to where Shenzhou 5 ______ for the rescue of China"s first astronaut.

单选题Not surprisingly, people in the northern part of the country, where the work ethic and the climate push the pace of life ever upward, ______permanently in the fast lane.