单选题A divorcee, Tom is the{{U}} sole {{/U}}provider in a typical "single parent" family.

单选题Hos advertisement is______ to attract much attention.

单选题It is hard to think of a major natural resource or pollution issue in North America today that does not affect rivers. Farm chemical runoff, industrial waste, urban storm sewers, sewage treatment, mining, logging, grazing, military bases, residential and business development, hydropower, loss of wetlands. The list goes on. Legislation like the Clear Water Act and Wild and Scenic Rivers Act have provided some protection, but threats continue. The Environmental Protection Agency (EPA) reported yesterday that an assessment of 642000 miles of rivers and streams showed 34 percent in less than good condition. In a major study of the Clean Water Act, the Natural Resources Defense Council last fall reported that poison runoff impairs more than 125000 miles of rivers. More recently, the NRDC and Izaak Walton League warned that pollution and loss of wetlands—made worse by last year's flooding—is degrading the Mississippi River ecosystem. On Tuesday, the conservation group American Rivers issued its annual list of 10 "endangered" and 20 "threatened" rivers in 32 states, the District of Columbia, and Canada. At the top of the list is the Clarks Fork of the Yellowstone River, where Canadian mining firms plan to build a 74-acre reservoir as part of a gold mine less than three miles from Yellowstone National Park. The reservoir would hold the runoff from the sulfuric acid used to extract gold from crushed rock. "In the event this tailings pond failed, the impact to the greater Yellowstone ecosystem would be cataclysmic and the damage irreversible. " Sen. Max Baucus (D) of Montana, chairman of the Environment and Public Works Committee, wrote to Noranda Minerals Inc. , an owner of the "New World Mine. " Last fall, an EPA official expressed concern about the mine and its potential impact, especially the plastic-lined storage reservoir. "I am unaware of any studies evaluating how a tailings pond could be maintained to ensure its structural integrity forever," said Stephen Hoffman, chief of the EPA's Mining Waste Section. "It is my opinion that underwater disposal of tailings at New World may present a potentially significant threat to human health and the environment. " The results of an environmental-impact statement, now being drafted by the forest Service and Montana Department of State Lands, could determine the mine's future... In its recent proposal to reauthorize the Clean Water Act, the Clinton administration noted "dramatically improved water quality since 1972," when the act was passed. But it also reported that 30 percent of rivers continue to be degraded, mainly by silt and nutrients from farm and urban runoff, combined sewer overflows, and municipal sewage. Bottom sediments are contaminated in more than 1000 waterways, the administration reported in releasing its proposal in January. Between 60 and 80 percent of riparian corridors (riverbank lands) have been degraded. As with endangered species and their habitats in forests and deserts, the complexity of ecosystems is seen in rivers and the effects of development—beyond the obvious threats of industrial pollution, municipal waters, and in-stream diversions to slake the thirst of new communities in dry regions like the Southwest... While there are many political hurdles ahead, reauthorization of the Clean Water Act this year holds promise for US fives. Rep. Norm Mineta (D) of California, who chairs the House committee overseeing the bill, calls it "probably the most important environmental legislation this congress will enact. /

单选题According to the latest population ______ the number of people in the world will go up an alarming 100 per cent. A. procedure B. proceeding C. process D. projection

单选题This distinguished director ______the plot for the prizewinning film while he was still a college student. A．conceived B．constituted C．reflected D．calculated

单选题When there are many conflicting opinions, it is hard to ______ the truth.

单选题For the people who have never traveled across the Atlantic the voyage is a fantasy. But for the people who cross it frequently one crossing of the Atlantic is very much like another, and they do not make the voyage for the 1 of its interest. Most of us are quite happy when we feel 2 to go to bed and pleased when the journey 3 . On the first night this time I felt especially lazy and went to bed 4 earlier than Usual. When I 5 my cabin, I was surprised 6 that I was to have a companion during my trip, which made me feel a little unhappy. I had expected 7 but there was a suitcase 8 mine in the opposite corner. I wondered who he could be and what he would be like. Soon afterwards he came in. He was the sort of man you might meet 9 , except that he was wearing 10 good clothes that I made up my mind that we would not 11 whoever he was and did not say 12 . As I had expected, he did not talk to me either but went to bed immediately. I suppose I slept for several hours because when I woke up it was already the middle of the night. I felt cold but covered 13 as well as I could and tried to go back to sleep. Then I realized that a 14 was coming from somewhere. I thought perhaps I had forgotten 15 the door, so I got up 16 the door but found it already locked from the inside. The cold air was coming from the window opposite. I crossed the room and 17 , the moon shone through it on to the other bed. 18 there. It took me a minute or two to 19 the door myself. I realized that my companion 20 through the window into the sea.

单选题Tom doesn’t think that the ______ situation here is as good as his hometown' s.

单选题Today, the Tower of London is one of the most popular tourist 1 and attracts over three million visitors a year. It was originally used as a Royal Palace for the Kings and Queens of England 2 the time of James I who 3 from 1603 to 1625, but is best known as a prison and 4 place Tower. Within the walls of the Tower, princes have been murdered, traitors 5 , spies shot, and Queens of England 6 . One of the most famous executions was that of Anne Boleyn in 1536. She was the second wife of Henry Ⅷ. He wanted to 7 her because she could not give him a son, so he 8 her of adultery. She was tried and found guilty. She asked to be beheaded with a sword, 9 the usual axe, which can still be seen in the Tower. The Tower was also the 10 of one of London"s most famous mysteries. King Edward IV died in 1483. His elder son, Edward, became king 11 his father"s death. Young Edward lived in the Tower, and the Duke of Gloucester, his protector, persuaded Edward"s brother, Richard, to come and live there so that they could play together. But then the Duke 12 that he was the new king, and he was crowned 13 the twelve-year-old Edward, 14 himself Richard Ⅲ. After that, the boys were seen less and less and 15 disappeared. It is said that they were suffocated in bed by pillows being 16 their mouths. It is believed that Richard Ⅲ 17 their deaths, although it has never been 18 . In 1674, workmen at the Tower discovered two skeletons which were taken away and buried in Westminster Abbey in 1678. The 19 were examined in 1933 and were declared to be those of two children, 20 the age of the Princes.

单选题Men could directly turn back to Greece and Rome for instruction, for correction, and for inspiration in the following fields of their work except ______.

单选题The evolution of sex ratios has produced, in most plants and animals with separate sexes, approximately equal numbers of males and females. Why should this be so? Two main kinds of answers have been offered. One is couched in terms of advantage to population. It is argued that the sex ratio will evolve so as to maximize the number of meetings between individuals of the opposite sex. This is essentially a "group selection" argument. The other, and in my view correct, type of answer was first put forward by Fisher in 1930. This "genetic" argument starts from the assumption that genes can influence the relative numbers of male and female offspring produced, by an individual carrying the genes. That sex ratio will be favored which maximizes the number of descendants an individual will have and hence the number of gene copies transmitted. Suppose that the population consisted mostly of females: then an individual who produced sons only would have more grandchildren. In contrast, if the population consisted mostly of males, it would pay to have daughters. If, however, the population consisted of equal numbers of males and females, sons and daughters would be equally valuable. Thus a one-to-one sex ratio is the only stable ratio; it is an "evolutionarily stable strategy." Although Fisher wrote before the mathematical theory of games had been developed, his theory incorporates the essential feature of a game-that the best strategy to adopt depends on what others are doing. Since Fisher's time, it has been realized that genes can sometimes influence the chromosome or gamete in which they find themselves so that the gamete will be more likely to participate in fertilization. If such a gene occurs on a sex-determining (X or Y) chromosome, then highly aberrant sex ratios can occur. But more immediately relevant to game theory are the sex ratios in certain parasitic wasp species that have a large excess of females. In these species, fertilized eggs develop into females and unfertilized eggs into males. A female stores sperm and can determine the sex of each egg she lays by fertilizing it or leaving it unfertilized. By Fisher's argument, it 'should still pay a female to produce equal numbers of sons and daughters. Hamilton, noting that the eggs develop within their host--the larva of another insect--and that the newly emerged adult wasps mate immediately and disperse, offered a remarkably cogent analysis. Since only one female usually lays eggs in a given larva, it would pay her to produce one male only, because this one male could fertilize all his sisters on emergence. Like Fisher, Hamilton looked for an evolutionarily stable strategy, but he went a step further in recognizing that he was looking for a strategy.

单选题For fear that a new shopping center would ruin the peace of the community, many residents ______ the construction plan.

单选题{{B}}Passage 4{{/B}} Violin prodigies, I learned, have come in distinct waves from distinct regions. Most of the great performers in the late 19th and early 20th centuries were born and brought up in Russia and Eastern Europe, I asked Isaac Stern, one of the world's greatest violinists the reason for this phenomenon. "It is very clear," he told me, "They were all Jews (犹太人) and Jews at the time were severely oppressed and ill-treated in that part of the world. They were not allowed into the professional fields, but they were allowed to achieve excellence on a concert stage." As a result, every Jewish parent's dream was to have a child in the music school because it was a passport to the West. Another element in the emergence of prodigies, I found, is a society that values excellence in a certain field to nurture (培育) talent. Nowadays, the most nurturing societies seem to be in the Far East. "In Japan, a most competitive society, with stronger discipline than ours." says Isaac Stem, children are ready to test their limits every day in many fields, including music. When Western music came to Japan after World War Ⅱ, that music not only became part of their daily lives, but it became a discipline as well. The Koreans and Chinese as we know, are just as highly motivated as the Japanese. That's a good thing, because even prodigies must work hard. Next to hard work, biological inheritance plays an important role in the making of a prodigy. J. S. Bach, for example, was the top of several generations of musicians, and four of his sons had significant careers in music.

单选题After the music had ______ there was a storm of applause.

单选题The official was arrested for inability to ______ all his fortune he has enjoyed.

单选题The story of Peter Pan is so fascinating that all the children like it.

单选题 Since the dawn of human ingenuity, people have devised ever more cunning tools to cope with work that is dangerous, boring, burdensome, or just plain nasty. That compulsion has resulted in robotics—the science of conferring various human capabilities on machines. And ff scientists have yet to create the mechanical version of science fiction, they have begun to come close. As a result, the modern world is increasingly populated by intelligent gizmos whose presence we barely notice but whose universal existence has removed much human labor. Our factories hum to the rhythm of robot assembly arms. Our banking is done at automated teller terminals that thank us with mechanical politeness for the transaction. Our subway trains are controlled by tireless robot-drivers. And thanks to the continual miniaturization of electronics and micro-mechanics, there are already robot systems that can perform some kinds of brain and bone surgery with submillimeter accuracy—far greater precision than highly skilled physicians can achieve with their hands alone. But if robots are to reach the next stage of laborsaving utility, they will have to operate with less human supervision and be able to make at least a few decisions for themselves—goals that pose a real challenge. "While we know how to tell a robot to handle a specific error," says Dave Lavery, manager of a robotics program at NASA, "we can't yet give a robot enough 'common sense' to reliably interact with a dynamic world." Indeed the quest for true artificial intelligence has produced very mixed results. Despite a spell of initial optimism in the 1960s and 1970s when it appeared that transistor circuits and microprocessors might be able to copy the action of the human brain by the year 2010, researchers lately have begun to extend that forecast by decades if not centuries. What they found, in attempting to model thought, is that the human brain's roughly one hundred billion nerve cells are much more talented—and human perception far more complicated—than previously imagined. They have built robots that can recognize the error of a machine panel by a fraction of a millimeter in a controlled factory environment. But the human mind can glimpse a rapidly changing scene and immediately disregard the 98 percent that is irrelevant, instantaneously focusing on the monkey at the side of a winding forest road or the single suspicious face in a big crowd. The most advanced computer systems on the earth can't approach that kind of ability, and neuroscientists still don't know quite how we do it.

单选题After an hour's discussion, the curriculum designers and computer programmers reached a consensus: that the new package of language learning materials should be both amusing and ______ for the users.