单选题We ______ the radio signals for help from the plane.

单选题Which of the following is True about affirmative action according to the text?

单选题Obviously, the per capita income of a country depends on many things, and any statistical test that does not take account of all important determinants is misspecified, and thus must be used only for descriptive and heuristic purposes. It is nonetheless interesting--and for many people surprising--to find that there is a positive and even a statistically significant relationship between these two variables: the greater the number of people per square kilometer the higher the per capita income. The law of diminishing returns is not invariably true. It would be absurd to suppose that a larger endowment of land ipso facto makes a country poorer. This consideration by itself would, of course, call for a negative sign on population density. Thus, it is interesting to ask what might account for the "wrong" sign and think of what statistical tests should ultimately be done. Clearly there is a simultaneous two-way relationship between population density and per capita income; the level of per capita income affects population growth just as population, by increasing the labor force, affects per capita income. The argument offered here suggests that perhaps countries with better economic policies and institutions come to have higher per capita incomes than countries with inferior policies and institutions, and that these higher incomes bring about a higher population growth through more immigration and lower death raters. In this way, the effects of better institutions and policies in raising per capita income swamps the tendency of diminishing returns to labor to reduce it. This hypothesis may also explain why many empirical studies have not been able to show a negative association between the rate of population growth and increases in per capita income. One reason why the ratio of natural resources to population does not account for variations in per capita income is that most economic activity can now readily be separated from deposits of raw material and arable land. Over time, transportation technologies have certainly improved, and products that have a high value in relation to their weight, such as most services and manufactured goods like computers and airplanes, may have become more important. The Silicon Valley is not important for the manufacturing of computers because of the deposits of silicon, and London and Zurich are not great banking centers because of fertile land. Even casual observation suggests that most modem manufacturing and service exports are not closely related to natural resources. Western Europe does not now have a high ratio of natural resources to population, but it is very important in the export of manufactures and services. In a parallel way, the striking success of Japan, Hong Kong, and Singapore, with relatively few natural resources per capita, cannot be explained by reliance thereon.

单选题An investigation of the circulation of blood in the eyes of diver has produced the strongest evidence that tissue damage caused by diving is more common and more severe than had been previously thought. Of the 26 professional divers studied, all had abnormal retinas. None of the divers taking part in the study had visual problems as a result of their damaged retinas but Alan Bird of Moorfields Eye Hospital in London said that he "would not be surprised to find divers whose damage has progressed far enough to affect their vision". Evidence has mounted during recent years to show that exposure to pressure during diving subtly damages the central nervous system. Doctors believe that the damage is due to obstruction in the flow of blood through the tissues. People who take up diving as a sport know they are at risk of getting "the bends" or an air embolism, but if they follow the correct procedures, the risk is very low. All professional divers know they also run the risk of bone necrosis. About 5 per cent of them develop small dead patches in their bones. Active professional divers have their thighs and upper arms X-rayed as part of their annual medical examination. Doctors have been concerned diving-caused dead patches to appear on bones; other tissues may be suffering a similar fate. Their concern increased in the early 1950s. Detailed neurological examinations and tests of the memory and reactions of experienced professional divers suggested that some of them might have slight damage to the brain and spinal cord. In order to determine the size of the problem, the researchers needed a method of looking for the damage in a large sample of divers that did not involve surgery. The damage which occurs in the tissue of both the bones and the nerves of divers is similar. Damages of the retina which doctors can see using the technique are known as retinal angiography. The process involves injecting fluorocein dye into the blood stream and photographing the back of the eye through the pupil. The technique can provide a detailed photograph of the two vascular systems supplying blood to their retina without causing too much discomfort to the patient. The researchers suggested three mechanisms to explain how diving causes this obstruction. When divers come back to the surface, air bubbles sometimes form in their lungs. Bubbles forming in the lungs trigger changes in the body's clotting mechanism which could result in minute clots. The researchers hope that clues to the cause of the obstruction will come from investigations into the individual differences between divers. Some of the divers studied had relatively little damage even though they had been diving for many years and done a great deal of deep diving. On the other hand, a few inexperienced divers had quite extensive damage.

单选题The Useverance/U of church and state is a basic principle of our government.

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

单选题A uniformed maid, whom Nicole estimated to be ______ the same age as herself, emerged from the house and crossed the porch to greet her warmly in Spanish.

单选题Peasants______ over 80 percent of the Chinese population

单选题The government has devoted a large slice of its national ______ to agriculture than most other countries.

单选题Mr. Johnson was a passionate person filled with an incredible dynamism. A. energy B. endurance C. effort D. endeavor

单选题Whatdoestheauthorthinkofintellect?

单选题On its last flight to the moon in 1972, the Apollo spacecraft ______ with a record lunar stay of seventy-five hours, which aroused worldwide excitement.

单选题For the teenagers who cast off their daily lives and head off for South America, Africa and Asia, it may offer the time of their young lives. But research published yesterday shows that the so-called "gap year" between school and university is not as beneficial as has been suggested. In five years the gap year has metamorphosed from a radical activity of a rebellious student generation into an obligation that must be fulfilled by ambitious future professionals. It has spawned in the process a lucrative commercial market providing tourist style trips. Prince William"s gap year venture to Chile in 2000 created institutional acceptability, and about 200,000 people a year between 18 and 25 now take 12 months out of study. "No longer were gap years for rebels and dropouts and people with nothing better to do; now they were for hopeful professionals and future kings," said Kate Simpson, from the school of geography at the university of Newcastle, who based her research on projects in South America and talked to hundreds of students on their return. "A gap year has become a requirement for success. It is now part of your progression to employability, as necessary as your A-levels and as inevitable as your degree. As the gap year has been professionalized, so it has increasingly been marketed at future professionals, with an assumption that further education and successful employment are to follow." Ms Simpson said that without explaining how values such as "broad horizons" and "character building" are supposed to be achieved by gap years, they have been promoted by people such as the foreign secretary, Jack Straw, and the University College Admission Service (Ucas). Mr. Straw said: "Our society can only benefit from travel which promotes character, confidence and decision-making skills." According to Ucas: "The benefits of a well-structured year out are now widely recognized by universities and colleges and cannot fail to stand you in good stead in later life." However, these statements did not always reflect the reality. Many of the 50 organizations, providing package trips for gap year students this year designed them to be acceptable to parents and future employers, and had little concern for the communities the students were volunteering to help. One example was in Ecuador where students had been sent to "help the local community." The villagers returned home from work to discover their houses had been painted by the volunteers without prior consultation. "Groups of 18-year-olds arrive somewhere with no skills and set about building a bridge or school often without proper consultation with the local community and what they might want or need. They get a level of experience and decision-making which they would not get at home, but also doing things in other people"s hospitals and schools they would never be allowed at home." Gap students had been involved in delivering babies, construction projects and teaching without prior training—something banned in Britain. A typical provider advertised: "Are you looking for a travel adventure with a purpose, one that gives you experience beyond tourism and provides practical help to local communities." Its slogan was: "Develop people. Share cultures. Build futures." For Ms Simpson, the industry "appears amateurish and outdated". The idea seemed to be that ancient, highly civilized cultures could benefit from the introduction of large numbers of unskilled 18-year-olds. "While such an approach may produce some valuable contributions, the risks are high. The gap year industry cannot rely on its good intentions to assure the quality of its work." The projects are often used to the benefit of the visiting students, as opposed to the residents. In many projects, the students practice being adults and professionals using local people as guinea pigs. "Projects did not have to be based on the exploitative and dehumanizing relationships. I am sure that many students learn a great deal from their gap years, but they could gain so much more if they experiment with local people." The best projects were those residents know in advance in which the local people participate and ask for what they want. "If the students and locals work together to form friendships, then the true potential of the gap year could be realized," Ms Simpson added.

单选题British Prime Minister Tony Blair promised the {{U}}electorate{{/U}} that guns would not be fired without an attempt to win a further U. N. sanction.

单选题It's absolutely ______ that you get that form sent off by the twenty-third of this month. A. vital B. fatal C. mortal D. neutral

单选题In our society the razor of necessity cuts close. You must make a buck to survive the day. You must work to make a buck. The job is often a chore, rarely a delight. No matter how demeaning the task, no matter how it dulls the senses or breaks the spirit, one must work. Lately there has been a questioning of this "work ethic", especially by the young. Strangely enough, it has touched off profound grievances in others hitherto silent and anonymous. Unexpected precincts are being heard from in a show of discontent by blue collar and white. On the evening bus the tense, pinched faces of young file clerks and elderly secretaries tell us more than we care to know. On the expressways middle-management men pose without grace behind their wheels, as they flee city and job. In all, there is more than a slight ache. And there dangles the impertinent question: Should there not be another increment, earned though not yet received, to one's daily work—an acknowledgment of a man's being? In fact, what all of us are looking for is a calling, not just a job. Jobs alone are not being enough for people.

单选题Overcoming setbacks takes time, efforts and perseverance .

单选题On the memorable occasion, the soldiers ______ the Colonel when he arrived. A. shouted B. solved C. salvaged D. saluted

单选题Visitors to India are often surprised to find that Taj Mahal is an almost ______ topic of conversation.