单选题Most people who travel long distance complain of jetlag. Jetlag makes business travel ers less productive and more prone (21) making mistakes. It is actually caused by (22) of your "body clock" —a small cluster of brain cells that controls the timing of biological (23) . The body clock is designed for a (24) rhythm of daylight and darkness, so that it is thrown out of balance when it (25) daylight and darkness at the "wrong" times in a new time zone. The (26) of jetlag often persist for days (27) the internal body clock slowly adjusts to the new time zone. Now a new anti-jetlag system is (28) that is based on proven (29) pioneering scien tific research. Dr. Martin Mooreede had (30) a practical strategy to adjust the body clock much sooner to the new time zone (31) controlled exposure to bright light. The time zone shift is easy to accomplish and eliminates (32) of the discomfort of jetlag. A successful time zone shift depends on knowing the exact times to either (33) or avoid bright light. Exposure to light at the wrong time can actually make jetlag worse. The proper schedule (34) light exposure depends a great deal on (35) travel plans.

单选题 Coincident with concerns about the accelerating loss of species and habitats has been a growing appreciation of the importance of biological diversity, the number of species in a particular ecosystem, to the health of the Earth and human beings. Much has been written about the diversity of terrestrial organisms, particularly the exceptionally rich life associated with tropical rain-forest habitats. Relatively little has been said, however, about diversity of life in the sea even though coral reef systems are comparable to rain forests in terms of richness of life. An alien exploring the Earth would probably give priority to the planet's dominant, most distinctive feature—the ocean. Humans have a bias toward land that sometimes gets in the way of truly examining global issues. Seen from far away, it is easy to realize that landmasses occupy one-third of the Earth's surface. Given that two-thirds of the Earth's surface is water and that marine life lives at all levels of the ocean, the total three- dimensional living space of the ocean is perhaps 100 times greater than that of land and contains more than 90 percent of all life on Earth even though the ocean has fewer distinct species. The fact that half of the known species are thought to inhabit the world's rain forests does not seem surprising, considering the huge numbers of insects that comprise the bulk of species. One scientist found many different species of ants in just one tree from a rain forest. While every species is different from every other species, their genetic makeup constrains them to be insects and to share similar characteristics with 750 000 species of insects. If basic, broad categories such as phyla and classes are given more emphasis than differentiating between species, then the greatest diversity of life is unquestionably the sea. Nearly every major type of plant and animal has some representation there. To appreciate fully the diversity of abundance of life in the sea, it helps to think small. Every spoonful of ocean water contains life on the order of 100 to 100 000 bacterial cells plus assorted microscopic plants and animals, including larva's or organisms ranging from sponges and corals to starfish and clams and much more.

单选题Few creations of big technology capture the imagination like giant dams. Perhaps it is humankind"s long suffering at the mercy of flood and drought that makes the ideal of forcing the waters to do our bidding so fascination. But to be fascinated is also, sometimes, to be blind Several giant dam projects threaten to do more harm than good. The lesson from dams is that big is not always beautiful. It doesn"t help that building a big, powerful dam has become a symbol of achievement for nations and people striving to assert themselves. Egypt"s leadership in the Arab world was cemented by the Aswan High Dam. Turkey"s bid for First World status includes the giant Ataturk Dam. But big dams tend not to work as intended. The Aswan Dam, for example stopped the Nile flooding but deprived Egypt of the fertile silt that floods left—all in return for a giant reservoir of disease which is now so full of silt that it barely generates electricity. And yet, the myth of controlling the waters persists. This week, in the heart of civilized Europe, Slovaks and Hungarians stopped just short of sending in the troops in their contention over a dam on the Danube. The huge complex will probably have all the usual problems of big dams. But Slovakia is bidding for independence from the Czechs, and now needs a dam to prove itself. Meanwhile, in India, the World Bank has given the go ahead to the even more wrong headed Narmada Dam. And the bank has done this even though its advisors say the dam will cause hardship for the powerless and environmental destruction. The benefits are for the powerful, but they are far from guaranteed. Proper scientific study of the impacts of dams and of the cost and benefits of controlling water can help to resolve these conflicts. Hydroelectric power and flood control and irrigation are possible without building monster dams. But when you are dealing with myths, it is hard to be either proper, or scientific. It is time that the world learned the lessons of Aswan. You don"t need a dam to be saved.

单选题Envy and jealousy of other people and their lives become ______ once you start believing in yourself.

单选题From the passage we may well understand that the author ______.

单选题It's a result more of ______ than anything else to win the top prize in a lottery.

单选题The government should ______ with the irrational regulations restricting drinking hours.

单选题As used in the first line of the second paragraph, the word "utter" means ______.

单选题FLOWER: VIOLET

单选题 In a stark ______ of fortunes, the Philippines—once Asia's second richest country recently had to beg Vietnam to sell its rice for its hungry millions.

单选题Six years later, in an about-face, the FBI admits that federal agents fired tear gas canisters capable of causing a fire at the Branch Davidian compound near Waco, Texas in 1993. But the law enforcement official said the firing came several hours before the structure burst into flames, killing 80 people including the Davidians' leader, David Koresh. "In looking into this, we've come across information that shows some canisters that can be deemed pyrotechnic in nature were fired—hours before the fire started," the official said. "Devices were fired at the bunker, not at the main structure where the Davidians were camped out." The Federal Bureau of Investigation maintains it did not start what turned to be a series of fiery bursts of flames that ended a 51-day standoff between branch members and the federal government. "This doesn't change the bottom line that David Koresh started the fire and the government did not," the official said. "It simply shows that devices that could probably be flammable were used in the early morning hours." The law enforcement official said the canisters were fired not at the main structure where the Davidian members were camped out but at the nearby underground bunker. They bounced off the bunkers concrete roof mad landed in an open field well, the official said. The canisters were fired at around 6 a.m., and the fire that destroyed the wooden compound started around noon, the official said. The official also added that other tear gas canisters used by agent that day were not flammable or potentially explosive. While Coulson denied the grenades played a role in starting the fire, his statement marked the first time that any U. S. government official has publicly contradicted the govemment's position that federal agents used nothing on the final day of the siege at Waco that could have sparked the fire that engulfed the compound. The cause of the fiery end is a major focus of an ongoing inquiry by the Texas Rangers into the Waco siege.

单选题"It was the beginning of a revolution in America and the world, a revolution that some have yet to acknowledge and many have yet to appreciate," says Harold Skramstad, president of the Henry Ford Museum in Dearborn, Michigan. 17767 No indeed: 1896, when Frank Duryea finally perfected the Duryea Motor Wagon. At its first airing, the contraption rolled less than 100 metres before the transmission froze up. But by the end of 1896 Duryea had sold 13 of them, thus giving birth to the American motor industry. That industry (whose roots, outside America, are usually attributed to tinkerings by Messrs Daimler and Benz in Germany) is being celebrated hugely over the coming months, culminating with a Great American Cruise in Detroit in June. "Our goal is to attract the greatest collection of antique and classic cars this nation has ever seen in one place at one time," says Mr. Skramstad modestly. Americans may indeed blame the car for almost everything that has happened to their country, and themselves, since 1896. The car has determined: The way they live. From cradle to grave, the car marks every rite of American passage. Home by car from the maternity ward; first driving licence (usually at the age of 16); first (backseat) sexual experience; first car of one's own (and the make of car is a prime determinant of social status, symbolic of everything a person is or does). In Las Vegas, and elsewhere, Americans can get married at drive-in chapels. They then buy, or lust after, a house with garages big enough for not one but two or three cars. This allocates more space to cars than to children. And when the time comes, they may lie in state at a drive-through funeral home, where you can pay your respects without pulling over. The way they shop. Main Street has been replaced by the strip mall and the shopping mall, concentrating consumer goods in an auto-friendly space. A large part of each shopping trip must now be spent, bags under chin, searching for the place where the car was left. (And another point: bags have annoyingly lost their carrying handles since shoppers ceased to be pedestrian) Since car-friendly living and shopping became the role, most builtup parts of America now look like every other part. There is simply no difference between a Burger Inn in California and one on the outskirts of Boston. The way they eat. A significant proportion of Americans' weekly meals are now consumed inside cars, sometimes while parked outside the (drive-by) eatery concerned, sometimes en route, which leads to painful spillages in laps, leading to overburdening of the legal system. Dozens of laws have been written to deal with car cases, ranging from traffic disputes to product liability. Drive-by shootings require a car, as do most getaways. The car is a great crime accessory; and it also causes the deaths of nearly 40,000 Americans every year. Personal finances. Before the age of the car, few people went into debt; no need to borrow money to buy a home. Now Americans tie themselves up with extended installment loans, and this in turn has spawned a whole financial industry. The wealth of the nation. By 1908, an estimated 485 different manufacturers were building cars in the United States. Employment grew nearly 100-fold in the industry during the first decade of the 20th century. When Henry Ford, in a stroke of genius, automated his production line he required a rush of new, unskilled labour, which he enticed by offering an unheard-of $ 5 a day in wages. Henceforth, workers could actually afford to buy what they built. And Americans never looked back. Today, the Big Three car manufacturers (Food, GM and Chrysler) generate more than $ 200 billion a year in business inside the United States. Directly and indirectly, the industry employs roughly one in seven workers. Every car job is reckoned to add $100,000 in goods and services to the economy, twice the national average. People occasionally suppose that the car is under attack as it enters its second century. Environmental regulators and transport planners (with their talk of car pools and subways) tend to give this impression. There are signs that personal computers may be replacing the sports car as the chief passion, and expense, of young men. But, in the end, nothing beats the idea of individual mobility. In a society that values freedom above all, the obvious way to celebrate a centenary is just to keep driving.

单选题Susan Clinton's participation in the Progressive Movement was far-reaching, embracing such causes as labor legislation and housing reforms.

单选题Summer holidays spent on the hot ghetto streets are __________ the time middle-class students devote to camps, exotic vacations and highly organized sports.

单选题All the musical instruments in the orchestra will be ______ before it starts.

单选题The relationship between exposure to ______ has not yet been determined.