单选题What is mainly discussed in the text?

单选题In the 18th century,New York was smaller than Philadelphia and Boston. Today it is the largest city in America. How to explain the change in its size and importance? To answer this question we must consider certain facts about geography, history and economics. Together these three will explain the huge growth of America's most famous cities. The map of the Northeast shows that four of the most heavily-populated areas in this region are around seaports. At these points materials from across the sea enter America, and the products of the land are sent there for export across the sea. Economists know that places where transportation lines meet are good places for making raw materials into completed goods. That is why seaports often have cities nearby. But cities like New York needed more than their geographical location in order to become great industrial centers. Their development did not happen simply by chance. About 1815 ,when many Americans from the east coast had already moved to the west, trade routes from the ports to the central regions of the country began to be a serious problem. The slow wagons of that time, drawn by horses or oxen, were too expensive for moving heavy freight very far. Americans had long admired Europe's canals. In New York State a canal seemed the best solution to the transportation problem. From the eastern end of Lake Erie all the way across the state to the Hudson River there is a long trip of low land. Here the Erie Canal was constructed. After working for several years it was completed in 1825. The canal produced an immediate effect. Freight costs were cut to about one-tenth of what they had been. New York City, which had been smaller than Philadelphia and Boston, quickly became the leading city of the coast. In later years, transportation routes on the Great Lakes were joined to routes on the Mississippi River. Then New York City became the end point of a great inland shipping system that extended from the Atlantic Ocean far up to the western branches of the Mississippi. The new railroads made canal shipping not as important as before, but it tied New York even more closely to the central regions of the country. It was easier for people in the central states to ship their goods to New York for export overseas. Exports from New York were greater than imports. Consequently, shipping companies were eager to fill their ships with passengers on the return trip from Europe. Passengers could come from Europe very cheaply as a result. Thus New York became the greatest port for receiving people from European countries. Many of them remained in the city. Others stayed in New York for a few weeks,months or years, and then moved to other parts of the United States. For these great numbers of new Americans, New York had to provide homes, goods and services. Their labor helped the city become great.

单选题Which areas in the U.S. have the greatest problems of homelessness and poverty?

单选题Large member countries like China and the U. S. ______.

单选题 The period of adolescence, i. e. , the period between childhood and adulthood, may be long or short, depending on social expectations and on society's definition as to what constitutes maturity and adulthood. In primitive societies adolescence is frequently a relatively short period of time, while in industrial societies with patterns of prolonged education coupled with laws against child labor, the period of adolescence is much longer and may include most of the second decade of one's life. Furthermore, the length of the adolescent period and the definition of adulthood status may change in a given society as social and economic conditions change. Examples of this type of change are the disappearance of the frontier in the latter part of the nineteenth century in the United States, and more universally, the industrialization of an agricultural society. In modern society, ceremonies for adolescence have lost their formal recognition and symbolic significance and there no longer is agreement as to what constitutes initiation ceremonies. Social ones have been replaced by a sequence of steps that lead to increased recognition and social status. For example, grade school graduation, high school graduation and college graduation constitute such a sequence, and while each step implies certain behavioral changes and social recognition, the significance of each depends on the socio-economic status and the educational ambition of the individual. Ceremonies for adolescence have also been replaced by legal definitions of status roles, rights privileges and responsibilities. It is during the nine years from the twelfth birthday to the twenty-first that the protective and restrictive aspects of childhood and minor status are removed and adult privileges and responsibilities are granted. The twelve-year-old is no longer considered a child and has to pay full fare for train, airplane, theater and movie tickets. Basically, the individual at this age loses childhood privileges without gaining significant adult rights. At the age of sixteen the adolescent is granted certain adult rights which increases his social status by providing him with more freedom and choices. He now can obtain a driver's license; he can leave public schools; and he can work without the restrictions of child labor laws. At the age of eighteen they also can marry without parental permission. At the age of twenty-one the individual obtains his full legal rights as an adult. He now can vote, he can buy liquor, he can enter into financial contracts, and he is entitled to run for public office. No additional basic rights are acquired as a function of age after majority status has been attained. None of these legal provisions determine at what point adulthood has been reached but they do point to the prolonged period of adolescence.

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单选题The Computer As a Mind Tool In Megatrends, his popular book on the direction of western society, John Naisbitt discusses the many trends that currently affect our lives. One important concept that he presents is the information society—that is, a society in which the majority of the workers are involved in the transmittal, or sending of information. Naisbitt notes that we have undergone a transition from an agrarian society to an industrial society to the current information society. The tools for such a society have existed for some time. These tools include the adding machine, the typewriter, the file cabinet, the television, and the telephone. The adding machine helps us work with numbers, the typewriter facilitates our work with characters, the file cabinet stores information in an easily retrievable fashion, the television portrays our ideas in pictures, and the telephone allows us to communicate with others instantaneously. However, the key element in the transition from an industrial society to an information society is a "wonder" called computer. The agrarian society depended on the metal plow and wheel, and the industrial society on the steam engine. The information society depends on the computer. Because the computer facilitates the work of the mind rather than manual labor, we refer to it as a mind tool—that is, a tool that extends, but does not replace, the human mind. The key idea behind the computer as a mind tool is that it performs all of the operations performed by the adding machine, typewriter, file cabinet, television, and telephone. On a computer, we can manipulate numbers as we do on a calculator (add, subtract, divide, multiply, and so on), we can manipulate letters of the alphabet as we do on a typewriter, and we can have the computer draw pictures based on these manipulations. Any of these symbols may be stored within the computer. Finally, we can communicate with other computer users over a telephone line. If a computer can do all of these things, just exactly how would it be described? Briefly, a computer is a machine that stores and manipulates symbols based on a series of user instructions called a program. This ability to execute a list of instructions differentiates the computer from a calculator and other office machines. In addition to the computer"s ability to perform all these tasks, two important characteristics of the computer make it the catalyst that generated the information society. These characteristics are speed and accuracy. The speed of a computer"s operations is measured in nanoseconds—billionths of a second—and the computer does exactly what it is instructed to do. These two characteristics can also lead to problems when the computer is given the wrong instructions. In this case, the computer quickly performs incorrect operations.

单选题 Questions 17—20 are based on the following passage.

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单选题Lacking a cure for AIDS, society must offer education, not only by public pronouncement but in classrooms. Those with AIDS or those at high risk of AIDS suffer prejudice; they are feared by some people who find living itself unsafe, while others conduct themselves with a "bravado" that could be fatal. AIDS has afflicted a society already short on humanism, open-handedness and optimism. Attempts to strike it out with the offending microbe are not abetted by pre-existing social ills. Such concerns impelled me to offer the first university level undergraduate AIDS course, with its two important aims. To address the fact the AIDS is caused by a virus, not by moral failure of societal collapse. The proper response to AIDS is compassion coupled with an understanding of the disease itself. We wanted to foster (help the growth of) the idea of a humane society. To describe how AIDS tests institutions upon which our society rests. The economy, the political sys- tem, science, the legal establishment, the media and our moral ethical-philosophical attitudes must respond to the disease. Those responses, whispered, or shrieked, easily accepted or highly controversial, must be put in order if the nation is to manage AIDS. Scholars have suggested that how a society deals with the threat of AIDS describes the extent to which that society has the right to call itself civilized. AIDS, then, is woven into the tapestry of modem society; in the course of explaining that tapestry, a teacher realizes that AIDS may bring about changes of historic proportions. Democracy obliges its educational system to prepare students to become informed citizens, to join their voices to the public debate inspired by AIDS. Who shall direct just what resources of manpower and money to the problem of AIDS? Even more basic, who shall formulate a national policy on AIDS? The educational challenge, then, is to enlighten the individual and the societal, or public responses to AIDS.

单选题The main reason for the latest rise of oil price is ______.

单选题The changing world of work is making American managers and professionals ______.