[外语类试卷]大学英语六级模拟试卷251及答案与解析.doc
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1、大学英语六级模拟试卷 251及答案与解析 一、 Part I Writing (30 minutes) 1 Direction: For this part, you are allowed 30 minutes to write a composition on the topic: Should Private Cars Be Encouraged in China. You should write at least 150 words and base your composition on the outline (given in Chinese) below: 1. 有些人认为有
2、必要发展私家车 2有些人持反对态度 3你的看法 二、 Part II Reading Comprehension (Skimming and Scanning) (15 minutes) Directions: In this part, you will have 15 minutes to go over the passage quickly and answer the questions attached to the passage. For questions 1-4, mark: Y (for YES) if the statement agrees with the info
3、rmation given in the passage; N (for NO) if the statement contradicts the information given in the passage; NG (for NOT GIVEN) if the information is not given in the passage. 1 World Population Growth and Distribution The United Nations, an accepted authority on population levels and trends, estimat
4、es that the world population reached 6 billion in 1999, and is increasing annually by more than 77 million persons. The rate of increase, 1.3 percent per year, has fallen below the peak rate of 2 percent per year attained by 1970. By the late 2040s, the UN estimates, the growth rate will have fallen
5、 to about 0.64 percent annually, at which time more than 50 countries will experience negative growth. A. Past and Present Growth Estimates of world population before 1900 are based on fragmentary (零散的 ) data, but scholars agree that, for most of human existence, long-run average population growth a
6、pproached approximately 0.002 percent per year, or 20 per million inhabitants. According to UN estimates, the population of the world was about 300 million in the year AD 1, and it took more than 1,500 years to reach the 500 million mark. Growth was not steady but was marked by oscillations (摆动 ) di
7、ctated by climate, food supply, disease, and war. Starting in the 17th century, great advances in scientific knowledge, agriculture, industry, medicine, and social organization made possible rapid acceleration in population growth. Machines gradually replaced human and animal labor. People slowly ac
8、quired the knowledge and means to control disease. By 1900 the world population had reached 1.65 billion, and by 1960 it stood at 3.04 billion. Beginning about 1950, a new phase of population growth was ushered in when famine and disease could be controlled even in areas that had not yet attained a
9、high degree of literacy or a technologically developed industrial society. This happened as a result of the modest cost of importing the vaccines (疫苗 ), antibiotics, insecticides, and high-yielding varieties of seeds produced since the 1950s. With improvements in water supplies, sewage-disposal faci
10、lities, and transportation networks, agricultural yields increased, and deaths from infectious and parasitic diseases greatly declined. Life expectancy at birth in most developing countries increased from about 35 40 years in 1950 to 66 years by 2000. The rapid decline in deaths among people who mai
11、ntained generally high fertility rates led to annual population growth that exceeded 3.1 percent in many developing nationsa-rate that doubles population size in 23 years. B. Regional Distribution As of 2000, 1.2 billion people lived in the developed nations of the world, and 4.9 billion people live
12、d in the less-developed countries. By region, over half the worlds population was in East and South Asia; China, with 1.3 billion inhabitants, and India, with some 1 billion, were the dominant contributors. Europe and the countries of the former USSR contained 14 percent, North and South America mad
13、e up 14 percent, Africa had 13 percent, and the Pacific Islands had about 1 percent of world population. Differences in regional growth rates are altering these percentages over time. Africas share of the world population is expected to more than double by the year 2025. The population of South Asia
14、 and Latin America is expected to remain nearly constant; in other regions, including East Asia, the population is expected to decline appreciably. The share of the present developed nations in world population-20 percent in 2000-is expected to fall to 15 percent by 2025. Nine out of every ten perso
15、ns who are now being added to the worlds population are living in the less-developed countries. C. Urban Concentration As a country develops from primarily an agricultural to an industrial economy, large-scale migration of rural residents to towns and cities takes place. During this process, the gro
16、wth rate of urban areas is typically double the pace of overall population increase. Some 29 percent of the world population was living in urban areas in 1950; this figure was 43 percent in 1990, and is projected to rise to 50 percent by the year 2005. Urbanization eventually leads to a severe decli
17、ne in the number of people living in the countryside, with negative population growth rates in rural areas. Rapid growth of overall population has deferred this event in most less-developed countries, but it is projected to occur in the early decades of the 21st century. Most migrants to the cities
18、can be assumed to have bettered themselves in comparison to their former standard of living, despite the serious problems of overcrowding, substandard housing, and inadequate municipal services that characterize life for many arrivals to urban centers. Dealing with these conditions, especially in ve
19、ry large cities, presents massive difficulties for the governments of less-developed countries. D. Population Projections Most of the potential parents of the next two decades have already been born. Population projections over this interval can, therefore, be made with reasonable confidence, barrin
20、g catastrophic changes. Beyond two decades, however, uncertainties about demographic magnitudes and other characteristics of human societies build up rapidly, making any projections somewhat speculative. Projections issued in 2000 show the world population increasing from 6.1 billion in 2000 to 7.9
21、billion in 2025 and 9.3 billion in 2050. “High“ and “low“ projections for 2025 are 8.4 billion and 7.5 billion respectively. The average world birth rate is projected to decline from the 1990 level of 26 per 1,000 to 22 per 1,000 at the end of the century and to 17.6 per 1,000 in 2025. Because of th
22、e expanding share of the population at high-mortality ages, the average world death rate is expected to decline only slightly; from 9 per 1,000 in 1990 to 8.4 in 2025. Average world life expectancy, however, is projected to rise from 65 years in 1990 to 71.3 years in 2025. Wide variations in populat
23、ion growth will undoubtedly persist. In the developed world, population growth will continue to be very low and in some nations will even decline. Western Europe as a whole is projected to have a declining population after 2000. U.S. Census Bureau projections, assuming middle fertility and mortality
24、 levels, show U.S. population increasing from 250 million in 1990 to 349 million in 2025 and 420 million in 2050. Thereafter, growth would be virtually zero. POPULATION POLICIES Government population policies seek to contribute to national development and welfare goals through measures that, directl
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