单选题The fossil remains of the first flying vertebrates, the pterosaurs, have intrigued paleontologists for more than two centuries. How such large creatures, which weighed in some cases as much as a piloted hang-glider and had wingspans from 8 to 12 meters, solved the problems of powered flight, and exactly what these creatures were—reptiles or birds—are among the questions scientists have puzzled over. Perhaps the least controversial assertion about the pterosaurs is that they were reptiles. Their skulls, pelvises, and hind feet are reptilian. The anatomy of their wings suggests that they did not e- valve into the class of birds. In pterosaurs a greatly elongated fourth finger of each forelimb supported a wing like membrane. The other fingers were short and reptilian, with sharp claws. In birds the second finger is the principal strut of the wing, which consists primarily of feathers. If the pterosaurs walked on all fours, the three short fingers may have been employed for grasping. When a pterosaur walked or remained stationary, the fourth finger, and with it the wing, could only turn upward in an extended inverted V-shape along each side of the animal"s body. The pterosaurs resembled both birds and bats in their overall structure and proportions. This is not surprising because the design of any flying vertebrate is subject to aerodynamic constraints. Both the pterosaurs and the birds have hollow bones, a feature that represents a savings in weight. In the birds, however, these bones are reinforced more massively by internal struts. Although scales typically cover reptiles, the pterosaurs probably had hairy coats. T.H. Huxley reasoned that flying vertebrates must have been warm-blooded because flying implies a high rate of metabolism, which in turn implies a high internal temperature. Huxley speculated that a coat of hair would insulate against loss of body heat and might streamline the body to reduce drag in flight. The recent discovery of a pterosaur specimen covered in long, dense, and relatively thick hair—like fossil material was the first clear evidence that his reasoning was correct. Efforts to explain how the pterosaurs became airborne have led to suggestions that they launched themselves by jumping from cliffs, by dropping from trees or even by rising into light winds from the crests of waves. Each hypothesis has its difficulties. The first wrongly assumes that the pterosaurs "hind feet resembled a bat"s and could serve as hooks by which the animal could hang in preparation for flight. The second hypothesis seems unlikely because large pterosaurs could not have landed in trees without damaging their wings. The third calls for high waves to channel updrafts. The wind that made such waves however, might have been too strong for the pterosaurs to control their flight once airborne.

单选题The Mitsubishi American company produces the following except for ______.

单选题The word "lewd'once referred to "ignorant", but now it is used to mean "lustful". This is an example of [A] narrowing of meaning. [B] widening of meaning. [C] loss of meaning. [D] meaning shift.

单选题{{B}}Text 3{{/B}} Conventional wisdom about conflict seems pretty much cut and dried. Too little conflict breeds apathy (冷漠) and stagnation (呆滞). Too much conflict leads to divisiveness (分裂) and hostility. Moderate levels of conflict, however, can spark creativity and motivate people in a healthy and competitive way. Recent research by Professor Charles R. Schwenk, however, suggests that the optimal level of conflict may be more complex to determine than these simple generalizations. He studied perceptions of conflict among a sample of executives. Some of the executives worked for profit seeking organizations and others for not-for-profit organizations. Somewhat surprisingly, Schwenk found that opinions about conflict varied systematically as a function of the type of organization. Specially, managers in not-for-profit organizations strongly believed that conflict was beneficial to their organizations and that it promoted higher quality decision-making than might be achieved in the absence of conflict. Managers of for-profit organizations saw a different picture. They believed that conflict generally was damaging and usually led to poor-quality decision making in their organizations. Schwenk interpreted these results in terms of the criteria for effective decision-making suggested by the executives. In the profit-seeking organizations, decision-making effectiveness was most often assessed in financial terms. The executives believed that consensus rather than conflict enhanced financial indicators. In the not-for-profit organizations, decision-making effectiveness was defined from the perspective of satisfying constituents. Given the complexities and ambiguities associated with satisfying many diverse constituents executives perceived that conflict led to more considered and acceptable decisions.

单选题 Questions 11-13 are based on the following monologue on American food. You now have 15 seconds to read Questions 11-13.

单选题[此试题无题干]

单选题Our Disappearing Wildlife Animal life first appeared on the earth about 400 million years ago. Through the passing millennia, thousands of animal species have come and gone. Until recently, this process was gradual, the result of changes in climate, in habitat, or in the genes of the animals themselves. But the tremendous expansion of modern civilization now threatens to upset this natural balance, putting unprecedented pressure on the survival of our wildlife. This imbalance can be traced to many causes. Most arise in the greed and poor planning of people. With each increase in our population, the wilderness areas where the animals live get smaller. The use of pesticides to control injurious insects also harms wild birds and animals. Water pollution kills fish in our rivers and oceans. Hunters have almost exterminated many of the larger animals like the big-horn sheep and the grizzly bear. As a result of this unrelenting pressure, our wildlife is disappearing at the rate of one species or subspecies per year. Of all the continents, the most drastic reduction in wildlife has occured in North America, where the transition from a rural to a highly industrialized society has been most rapid. Among the victims are birds, mammals, and fish. We will never again see the passenger pigeon or the eastern elk. They have been wiped out. Of many other species, only a few representatives still survive in the wild. Animals that kill other animals for food are called predators. The predators include the wolf, mountain lion, fox, bobcat and bear. Attack against these animals began with the arrival of the first European settlers, who wished to protect their livestock. Yet every animal, including the predator, has its place in nature"s grand design. Predators help maintain the health of their prey species by eliminating the diseased, young, old, and injured. Predators like the mountain lion and the wolf help to keep the deer herds healthy. Their kill also provides food for scavengers that feed on carrion. Occasional loss of livestock must be weighed against the good these animals do in maintaining the balance of nature. Overhunting an animal is an obvious form of extermination, but there are more subtle processes that often have the same fatal result. One of these is destruction of habitat. When farmers introduced sheep and cattle to North America, the domestic animals competed with the wild animals for the available grazing land. Animals like the buffalo and the pronghorn antelope, which once roamed the plains in countless numbers, were either killed or pushed off the grasslands. Pesticides have also taken their toll. In 1947, new chemical poison called DDT was introduced. It proved very effective in controlling insect pests like the potato beetle and the boll weevil. But pesticides, which decompose very slowly, accumulate in animals which feed on pest insects or their predators, and the accumulated poisons attack their nervous systems. Pesticides also interfere with the formation of calcium in birds, which lay eggs with very thin shells or no shell at all. When wildlife fail to reproduce, it isn"t very long before they disappear. Why should we care about the extinction of these birds and animals? The answer is simple enough. Every species that becomes extinct is gone forever. With each departure a small part of the diversity of nature that makes life so interesting is also gone. What has man got to look forward to—endless cities and houses and roads that cross barren country devoid of birds and animals? Is that the world we want for ourselves and our children?

单选题______ got out of the room, ______ the telephone rang. A. He hardly; then B. Hardly had he; when C. He had not; than D. Not had he; when

单选题The American Council on graduate, medical education is

单选题 The United States has historically had higher rates of marriage than those of other industrialized countries. The current annual marriage {{U}} {{U}} 1 {{/U}} {{/U}}in the United States—about 9 new marriages for every 1,000 people—is {{U}} {{U}} 2 {{/U}} {{/U}}higher than it is in other industrialized countries. However, marriage is {{U}} {{U}} 3 {{/U}} {{/U}}as widespread as it was several decades ago. {{U}} {{U}} 4 {{/U}} {{/U}}of American adults who are married {{U}} {{U}} 5 {{/U}} {{/U}}from 72 percent in 1970 to 60 percent in 2002. This does not mean that large numbers of people will remain unmarried {{U}} {{U}} 6 {{/U}} {{/U}}their lives. Throughout the 20th century, about 90 percent of Americans married at some {{U}} {{U}} 7 {{/U}} {{/U}}in their lives. Experts {{U}} {{U}} 8 {{/U}} {{/U}}that about the same proportion of today's young adults will eventually marry. The timing of marriage has varied {{U}} {{U}} 9 {{/U}} {{/U}}over the past century. In 1995 the average age of women in the United States at the {{U}} {{U}} 10 {{/U}} {{/U}}of their first marriage was 25. The average age of men was about 27. Men and women in the United States marry {{U}} {{U}} 11 {{/U}} {{/U}}the first time at an average of five years later than people {{U}} {{U}} 12 {{/U}} {{/U}}in the 1950s. {{U}} {{U}} 13 {{/U}} {{/U}}, young adults of the 1950s married younger than did any previous {{U}} {{U}} 14 {{/U}} {{/U}}in U. S. history. Today's later age of marriage is {{U}} {{U}} 15 {{/U}} {{/U}}the age of marriage between 1890 and 1940. {{U}} {{U}} 16 {{/U}} {{/U}}, a greater proportion of the population was married (95 percent) during the 1950s than at any time before {{U}} {{U}} 17 {{/U}} {{/U}}. Experts do not agree on {{U}} {{U}} 18 {{/U}} {{/U}}the "marriage rush" of the late 1940s and 1950s occurred, but most social scientists believe it represented a {{U}} {{U}} 19 {{/U}} {{/U}}to the return of peaceful life and prosperity after 15 years of severe economic {{U}} {{U}} 20 {{/U}} {{/U}}and war.

单选题Questions 14-16 are based on a report about the death rate from influenza. You now have 15 seconds to read Questions 14--16.