单选题Researchers are looking for new ways to ______ the problem. A. abridge B. approach C. condense D. dispose

单选题Even though strong evidence has proved the nicotine to be ________, the tobacco company still insists that its products are harmless.

单选题Wherever there is matter, there is energy; all changes of matter______changes in the form of the energy.

单选题Forget what Virginia Woolf said about What a writer needs-a room of one's own. The writer she had in mind wasn't at work on a novel in cyberspace, one with multiple hypertexts, animated graphics and downloads of trancey, chiming music. For that you also need graphic interfaces, ReslPlayer and maybe even a computer laboratory at Brown University. That was where Mark Amerika—his legally adopted name; don't ask him about his birth name-composed much of his novel Grammatron. But Grammatron isn't just a story. It's an online narrative (grammatron. com) that uses the capabilities of cyberspace to tie the conventional story line into complicated knots. In the four years it took to produce—it was completed in 1997—each new advance in computer software became another potential story device. "I became sort of dependent on the industry", jokes Amerika, who is also the author of two novels printed on paper." That's unusual for a writer, because if you just write on paper the" technology is pretty stable." Nothing about Grammatron is stable. At its center, if there is one, is Abe Golam, the inventor of Nanoscript, a quasi-mystical computer code that some unmystical corporations are itching to acquire. For much of the story, Abe wanders through Prague-23, a virtual "city" in cyberspace where visitors indulge in fantasy encounters and virtual sex, which can get fairly graphic. The reader wanders too, because most of Grammatron's 1,000-plus text screens contain several passages in hypertext. To reach the next screen, just double-click. But each of those hypertexts is a trapdoor that can plunge you down a different pathway of the story. Choose one and you drop into a corporate- strategy memo, Choose another and there's a XXX- rated sexual rant. The story you read is in some sense the story you make. Amerika teaches digital art at the University of Colorado, where his students develop works that straddle the lines between art, film and literature. "I tell them not to get caught up in mere plot," he says. Some avant-garde writers—Julio Cortazar, Italo Calvino-have also experimented with novels that wander out of their author's control. "But what makes the Net so exciting," says Amerika, "is that you can add sound, randomly generated links, 3-D modeling, animation." That room of one's own is turning into a fun house.

单选题You will find the scenery is so beautiful if you view from the ______ of the hill. A. ceiling B. summit C. mantle D. roof

单选题Although Venus is the nearest planet of the Earth, little is known about it because it is ______ covered by thick clouds.

单选题In the decades between 1910 and 1930, over ten percent of the Black population of the United States left the South, where the majority of the Black population had been located, and migrated to northern states, with the largest number moving, it is claimed, between 1916 and 1918. It has been frequently assumed, but not proved, that most of the migrants in what has come to be called the Great Migration came from rural areas and were motivated by two concurrent factors: the collapse of cotton industry following boll-weevil infestation, which began in 1898, and increased demand in the North for labor following the cessation of European immigration caused by the outbreak of the first World War in 1914. This assumption has led to the conclusion that the migrant's subsequent lack of economic mobility in the North is tied to rural background, a background that implies unfamiliarity with urban living and a lack of industrial skills. But the question of who actually left the South has never been investigated in detail. Although numerous investigations document a flight from rural southern areas to southern cities prior to the Great Migration, no one has considered whether the same migrants then moved on to northern cities. In 1910 over 600,000 Black workers, or ten percent of the Black work force reported themselves to be engaged in "manufacturing and mechanical pursuits", the federal census category roughly including the entire industrial sector. The Great Migration could easily have been made up entirely of this group and their families. It is perhaps surprising to argue that an employed population could be tempted to move, but an explanation lies in the labor conditions then prevalent in the South. About thirty-five percent of the urban Black population in the South was engaged in skilled trades. Some were from the old artisan class of slavery—blacksmiths, masons, carpenters—which had a monopoly of certain trades, but they were gradually being pushed out by competition, mechanization, and obsolescence. The remaining sixty-five percent, more recently urbanized, worked in newly developed industries—tobacco, lumber, coal and iron manufacture, and railroads. Wages in the South, however, were low, and Black workers were aware, through labor recruiters and the Black press, that they could earn more even as unskilled workers in the North than they could as artisans in the South. After the boll-weevil infestation, urban Black workers faced competition from the continuing influx of both Black and White rural workers, who were driven to undercut the wages formerly paid for industrial jobs. Thus, a move north would be seen as advantageous to a group that was already urbanized and steadily employed, and the easy conclusion tying their subsequent economic problems in the North to their rural backgrounds comes into question.

单选题Can't you speak more ______ to your parents?

单选题Every community requires a Uwholesome/U, dependable supply of water, and every community generates liquid and solid wastes.

单选题The two countries were fighting severely to______every inch of the land. (2009年北京航空航天大学考博试题)

单选题Any troop of wild animals should be approached Uwarily/U.

单选题Emerging from the 1980 census is the picture of a nation developing more and more regional competition, as population growth in the Northeast and Midwest reaches a near standstill. This development—and its strong implications for U.S. politics and economy in years ahead—has enthroned the South as America"s most densely populated region for the first time in the history of the nation"s head counting. Altogether, the U.S. population rose in the 1970s by 23.2 million people—numerically the third largest growth ever recorded in a single decade. Even so, that gain adds up to only 11.4 percent, lowest in American annual records except for the Depression years. Americans have been migrating south and west in larger number since World War Ⅱ, and the pattern still prevails. Three sun belt states—Florida, Texas and California—together had nearly 10 million more people in 1980 than a decade earlier. Among large cities, San Diego moved from 14th to 8th and San Antonio from 15th to 10th—with Cleveland and Washington. D. C, dropping out of the top 10. Not all that shift can be attributed to the movement out of the snow belt, census Officials say, Nonstop waves of immigrants played a role, too—and so did bigger crops of babies as yesterday"s "baby boom" generation reached its child bearing years. Moreover, demographers see the continuing shift south and west as joined by a related but newer phenomenon: More and more, Americans apparently are looking not just for places with more jobs but with fewer people, too. Some instances: Regionally, the Rocky Mountain states reported the most rapid growth rate—37.1 percent since 1970 in a vast area with only 5 percent of the U.S. population. Among states, Nevada and Arizona grew fastest of all: 63.5 and 53.1 percent respectively. Except for Florida and Texas, the top 10 in rate of growth is composed of Western states with 7.5 million people—about 9 per square mile. The flight from over crowdedness affects the migration from snow belt to more bearable climates. Nowhere do 1980 census statistics dramatize more the American search for spacious living than in the Far West. There, California added 3.7 million to its population in the 1970s, more than any other state. In that decade, however, large numbers also migrated from California, mostly to other parts of the West. Often they chose—and still are choosing—somewhat colder climates such as Oregon, Idaho and Alaska in order to escape smog, crime and other plagues of urbanization in the Golden State. As a result, California"s growth rate dropped during the 1970s, to 18.5 percent—little more than two thirds the 1960s growth figure and considerably below that of other Western states.

单选题One reason for the successes of Asian immigrants in the U. S. is that they have taken great ______ to educate their children. A. efforts R pains C. attempts D. endeavors

单选题She ______ and lowered her head when she couldn"t answer the question in the presence of her classmates.

单选题Could a husband sell his wife's inheritance?

单选题Since Japan______importance to education and technological innovation, its economy has developed at a high speed.(2002年上海交通大学考博试题)

单选题You may have wondered why the supermarkets are all the same. It is not because the companies that operate them lack imagination. It is because they all aim at persuading people to buy things. In the supermarket, it takes a while for the mind to get into a shopping mode. This is why the area immediately inside the entrance is known as the " decompression zone". People need to slow down and look around, even if they are regulars. In sales terms this area is bit of a loss, so it tends to be used more for promotion. Immediately inside the first thing shoppers may come to is the fresh fruit and vegetables section. For shoppers, this makes no sense. Fruit and vegetables can be easily damaged, so they should be bought at the end, not the beginning, of a shopping trip. But what is at work here? It turns out that selecting good fresh food is a way to start shopping, and it makes people feel less guilty about reaching for the unhealthy stuff later on. Shoppers already know that everyday items, like milk, are invariably placed towards the back of a store to provide more opportunities to tempt customers. But supermarkets know shoppers know this, so they use other tricks, like placing popular items halfway along a section so that people have to walk all along the aisle looking for them. The idea is to boost "dwell time" : the length of time people spend in a store. Traditionally retailers measure "football" , as the number of people entering a store is known, but those numbers say nothing about where people go and how long they spend there. But nowadays, a piece of technology can fill the gap: the mobile phone. Path Intelligence, a British company tracked people's phones at Gunwharf Quays, a large retailer centre in Portsmouth — not by monitoring calls, but by plotting the positions of handsets as they transmit automatically to cellular networks. It found that when dwell time rose 1 $ sales rose 1. 3% . Such techniques are increasingly popular because of a deepening understanding about how shoppers make choices. People tell market researchers that they make rational decisions about what to buy, considering things like price, selection or convenience. But subconscious forces, involving emotion and memories, are clearly also at work.

单选题Swimmers can drown in busy swimming pools when lifeguards fail to notice that they are in trouble. The Royal Society for the Prevention of Accidents says that on average 15 people drown in British pools each year, but many more suffer major injury after getting into difficulties. Now a French company has developed an artificial intelligence system called Poseidon that sounds the alarm when it sees someone in danger of drowning. When a swimmer sinks towards the bottom of the pool, the new system sends an alarm signal to a poolside monitoring station and a lifeguard's pager. In trials at a pool in Ancenis, near Nantes, it saved a life within just a few months, says Alistair McQuade, a spokesman for its manufacturer, Poseidon Technologies. Poseidon keeps watch through a network of underwater and overhead video cameras. AI software analyses the images to work out swimmers, trajectories. To do this reliably, it has to tell the difference between a swimmer and the shadow of someone being cast onto the bottom or side of the pool. "The underwater environment is a very dynamic one, with many shadows and reflections dancing around." Says McQuade. The software does this by "projecting" a shape in its field of view onto an image on the far wall of the pool. It does the same with an image from another camera viewing the shape from a different angle. If the two projections are in the same position, the shape is identified as a shadow and is ignored. But if they are different, the shape is a swimmer and so the system follows its trajectory. To pick out potential drowning victims, anyone in the water who starts to descend slowly is added to the software's "pre-alert" list, says McQuade. Swimmers who then stay immobile on the pool bottom for 5 seconds or more are considered in danger of drowning. Poseidon double-checks that the image really is of a swimmer, not a shadow, by seeing whether it obscures the pool's floor texture when viewed from overhead. If so, it alerts the lifeguard, showing the swimmer's location on a poolside screen. The first full-scale Poseid6n system will be officially opened next week at a pool in High Wycombe, Buckinghamshire. One man who is impressed with the idea is Travor Baylis, inventor of the clockwork radio. Baylis runs a company that installs swimming pools—and he was once an underwater escapologist with a circus. "I say full marks to them if this works and can save lives," he says. But he adds that any local authority spending ￡30,000— plus on a Poseidon system ought to be investing similar amounts in teaching children to swim.

单选题Among the more colorful characters of Leadville"s golden age were H.A.W.Tabor and his second wife, Elizabeth McCourt, better known as "Baby Doe". Their history is fast becoming one of the legends of the Old West. Horace Austin Warner Tabor was a school teacher in Vermont. With his first wife and two children he left Vermont by covered wagon in 1855 to homes tread in Kansas. Perhaps he did not find farming to his liking, or perhaps he was lured by rumors of fortunes to be made in Colorado mines. At any rate, a few years later he moved west to the small Colorado mining camp known as California Gulch, which he later renamed Leadville when he became its leading citizen. "Great deposits of lead are sure to be found here." he said. As it turned out, it was silver, not lead, that was to make Leadville"s fortune and wealth. Tabor knew little about mining himself, so he opened a general store, which sold everything from boots to salt, flour, and tobacco. It was his custom to "grubstake" prospective miners, in other words, to supply them with food and supplies, or "grub", while they looked for ore, in return for which he would get a share in the mine if one was discovered. He did this for a number of years, but no one that he aided ever found anything of value. Finally one day in the year 1878, so the story goes, two miners came in and asked for "grub". Tabor had decided to quit supplying it because he had lost too much money that way. These were persistent, however, and Tabor was too busy to argue with them. "Oh help yourself. One more time wont"s make any difference," he said and went on selling shoes and hats to other customers. The two miners took $17 worth of supplies, in return for which they gave Tabor a one-third interest in their findings. They picked a barren place on the mountainside and began to dig. After nine days they struck a rich vein of silver. Tabor bought the shares of the other two men, and so the mine belonged to him alone. This mine, known as the "Pittsburgh Mine," made 1,300,000 for Tabor in return for his $17 investment. Later Tabor bought the Matchless Mine on another barren hillside just outside the town for $17,000. This turned out to be even more fabulous than the Pittsburgh, yielding $35,000 worth of silver per day at one time. Leadville grew. Tabor became its first mayor, and later became lieutenant governor of the state.