单选题Ford Abandons Electric Vehicles The Ford motor company's abandonment of electric cars effectively signals the end of the road for the technology, analysts say. General Motors and Honda ceased production of battery-powered cars in 1999, to focus on fuel cell and hybrid electric gasoline engines, which are more attractive to the consumers. Ford has now announced it will do the same. Three years ago, the company introduced the Think City two-seater car and a golf cart called the THINK, or Think Neighbor. It hoped to sell 5,000 cars each year and 10,000 carts. But a lack of demand means only about 1,000 of the cars have been produced, and less than 1,700 carts have been sold so far in 2002. "The bottom line is we don't believe that this is the future of environment transport for the mass market," Tim Holmes of Ford Europe said on Friday. "We feel we have given electric our best shot." The Think City has a range of only about 53 miles and up to a six-hour battery recharge time. General Motors' EVI electric vehicle also had a limited range of about 100 miles. The very expensive batteries also mean electric cars cost much more than petrol- powered alternatives. An electric Toyota RAV4 EV vehicle costs over $ 42,000 in the US, compared with just $17,000 for the petrol version. Toyota and Nissan are now the only major automanufacturers to produce electric vehicles. "There is a feeling that battery electric has been given its chance. Ford now has to move on with its hybrid program, and that is what we will be judging them on, "Roger Higman, a senior transport campaigner at UK Friends of the Earth, told the Environment News Service. Hybrid cars introduced by Toyota and Honda in the past few years have sold well. Hybrid engines offer greater mileage than petrol—only engines, and the batteries recharge themselves. Ford says it thinks such vehicles will help it meet planned new guidelines "on vehicle emissions" in the US. However, it is not yet clear exactly what those guidelines will permit. In June, General Motors and Daimler Chrysler won a court injunction, delaying by two years Californian legislation requiring car-makers to offer 100,000 zero-emission and other low-emission vehicles in the state by 2003. Car manufacturers hope the legislation will be rewritten to allow for more low-emission, rather than zero-emission, vehicles.

单选题It's impolite to cut in when two persons are holding a conversation.

单选题In the first decades of the twentieth century, the individual gene could not be seen, but could be worked with {{U}}fruitfully{{/U}}.

单选题She exhibited great powers of endurance during the climb.A. playB. sendC. showD. tell

单选题The ice is not thick enough to bear the weight of a tank.

单选题These are the motives for doing it. A. reasons B. excuses C. answers D. replies

单选题The writer decided to quit smoking partly because

单选题The Romance of Arthur Most cultures have some sort of hero who represents the best values of what its people believe in. The unusual thing about King Arthur is that legends of his heroism have persisted for several centuries and spread far beyond England, the place where they began. The earliest stories of King Arthur represent him as a warrior who fought and subdued the invading Norsemen in the years around A D 700. This much of the Arthurian tale is probably based on fact. Whether called Arthur or not, there is a body of evidence supporting the existence of such a warrior. It is the later embellishment of the tale whose authentic city is questionable. According to these, Arthur was born in a castle in Tintagel on the stormy western coast of England and because he was the illegitimate son of King Uther Pendragon, he was spirited away by the magician Merlin and his true identity kept from him. He became king after freeing the sword Excalibur from the stone into which it was thrust. He married the beautiful Guinevere and assembled in his court all the noblest knights of the land, including Lancelot, with whom Guinevere would later be unfaithful to him. He was finally defeated in battle by his illegitimate son Mordred, and his body was spirited away to the isle of Avalon. This romantic tale greatly appealed to the English and the French in the Middle Ages, when the code of chivalry—ideal qualities of knighthood—constituted an important part of many stories. Tales of the heroism of Galahad, Percival, Gawain, and many other of Arthur"s knights were circulated as well. In England today, there are many sites claiming apiece of the Arthurian a legend. There is a mined castle at Tintagel. Near Glastonbury are the remains of an ancient abbey where Arthur"s and Guinevere"s bodies were supposedly exhumed in the 12th century. Neither of these proves that the legend is true, but they do keep its mystique alive.

单选题The United States is trying to deal with the serious problems brought on by the energy crisis.

单选题All living organisms, regardless of their unique identity, have certain biological, chemical, and physical characteristics in common.

单选题How does Science Proceed? How exactly does science work? How do scientists go about "doing" science? Ordinarily we think science proceeds in a straightforward way. Ideally, scientists make observations, formulate hypotheses, and test those hypotheses by making further observations. When there is difference between what is observed and what is predicted by the hypothesis, the hypothesis is reviewed. Science proceeds in this way, which is a gradual method of finding the best fit between observation and prediction. But this idealized version of how one "does" science is naive. Although science demands proof that observations made by one observer be observable by other observers using the same methods, it is by no means clear that even when confronted with identical phenomena different observers will report identical observations. And it is most certain that, even if the same observations are made, the conclusions as to the meaning of the observations frequently differ. The fact is that all of us scientists included, see differently. Variations in human perception are well known and have been studied extensively. Distortions in perceptions are frequently seen among observers, even though they may be in identical settings viewing identical phenomena. A documented misperception from history can be found in the experience of Darwin. His ship, Beagle, after anchoring off the Patagonian coast, sent off a landing party in small rowboats. Amazingly, the Patagonian natives watching from shore were blind to the Beagle, but could easily see the tiny rowboats. They have no prior experience of huge sailing ships, but small rowing vessels were an everyday part of their life. Rowboats fit their model of the world but huge ships did not. Their model determined their perceptions. Our ideas that science proceeds on an utterly objective and straightforward basis ignores the distortions of reality imposed by our own perceptual apparatus. In many cases we see what we have been trained to see. What we are used to seeing. If a subject is fitted with special glasses that are designed to invert the visual field, at first the subject sees everything upside down. After a period of time, as the glasses continue to be worn, a correction is made by our perceptual mechanism and the image is flipped, so that the world once again appears erect.

单选题The Best Way to Reduce Your Weight You hear this: "No wonder you are fat. All you ever do is eat." You feel sad: "I skip my breakfast and supper. I run every morning and evening. What else can I do?" Basically you can do nothing. Your genes, not your life habits, determine your weight and your body constantly tries to maintain it. Albert Stunkard of the University of Pennsylvania found from experiments that, "80 percent of the children of two obese (肥胖的) parents become obese, as compared with no more than 14 percent of the offspring of two parents of normal weight." How can obese people become normal or even thin through dieting? Well, dieting can be effective, but the health costs are tremendous. Jules Hirsch, a research physician at Rockefeller University, did a study of eight fat people. They were given a liquid formula providing 600 calories a day. After more than 10 weeks, the subjects lost 45ka on average. But after leaving the hospital, they all regained weight. The results were surprising: by metabolic (新陈代谢的) measurement, fat people who lost large amounts of weight seemed like they were starving. They had psychiatric problems. They dreamed of food or breaking their diet. They were anxious and depressed; some were suicidal. They hid food in their rooms. Researchers warn that it is possible that weight reduction doesn"t result in normal weight, but in an abnormal state resembling that of starved non-obese people. Thin people, however, suffer from the opposite: They have to make a great effort to gain weight. Ethan Sims, of the University of Vermont, got prisoners to volunteer to gain weight. In four to six months, they ate as much as they could. They succeeded in increasing their weight by 20 to 25 percent. But months after the study ended they were back to normal weight and stayed there. This did not mean that people are completely without hope in controlling their weight. It means that those who tend to be fat will have to constantly battle their genetic inheritance if they want to significantly lower their weight. The findings also provide evidence for something scientists thought was true-each person has a comfortable weight range. The range might be as much as 9kg. Someone might weigh 60～69kg without too much effort. But going above or below the natural weight range is difficult. The body resists by feeling hungry or full and changing the metabolism to push the weight back to the range it seeks.

单选题John removed his overcoat.A. took awayB. left asideC. took offD. washed off

单选题Ants Have Big Impact on Environment as "Ecosystem Engineers" Research by the University of Exeter has revealed that ants(蚂蚁) have a big impact on their local environment as a result of their activity "asecosystem engineers" and predators. The study, published in the Journal of Animal Ecology, found that ants have two distinct effects on their local environment. Firstly, through moving of soil by nest building activity and by collecting food they affect the level of nutrients in the soil. This can indirectly impact the local populations of many animal groups, from decomposers to species much higher up the food chain. Secondly, they prey on a wide range of other animals, including larger prey which can be attacked by vast numbers of ant workers. Dirk Sanders, an author of the study from the university"s Centre for Ecology and Conservation, said: "Ants are very effective predators which thrive in huge numbers. They"re also very territorial and very aggressive, defending their resources and territory against other predators. All of this means they have a strong influence on their surrounding area." "In this research, we studied for the first time how big this impact is and the subtleties of it. What we found is that despite being predators, their presence can also lead to an increase in density and diversity of other animal groups. They genuinely play a key role in the local enviromnent, having a big influence on the grassland food web." Sanders said. The study, carried out in Germany, studied the impact of the presence of different combinations and densities of black garden ants and common red ants, both species which can be found across Europe, including in the UK. It found that a low density of ants in an area increased the diversity and density of other animals in the local area, particularly the density of herbivores and decomposers. At higher densities ants had no or the opposite effect, showing that predation is counteracting the positive influence. Dr. Frank van Veen, another author on the study, said: "What we find is that the impact of ants on soil nutrient levels has a positive effect on animal groups at low levels, but as the number of ants increases, their predatory impacts have the bigger effect—thereby counteracting the positive influence via ecosystem engineering." Ants are important components of ecosystems not only because they constitute a great part of the animal biomass but also because they act as ecosystem engineers. Ant biodiversity is incredibly high and these organisms are highly responsive to human impact, which obviously reduces its richness. However, it is not clear how such disturbance damages the maintenance of any services to the ecosystem. Ants are important in below ground processes through the alteration of the physical and chemical environment and through their effects on plants, microorganisms, and other soil organisms.

单选题7 The researchers have just completed a study of driving situations.A. startedB. finishedC. changedD. made

单选题A beautiful woman attended to me in that store yesterday.

单选题The document was compiled by the Department of Health.

单选题Her sister urged her to apply for the job.______

单选题A larg crowd assembled outside the American embassy.

单选题Everybody was {{U}}glad to{{/U}} see Mary back