完形填空Many of the world’s pollution problems have been caused by the crowding of large groups of people into cities.Satisfying the 21 of the people leads to further polluting by industry.If the rapid increase in human population 22 at the present rate (比率),

Directions:In this section, there is one passage followed by a summary. Read the passage carefully and complete the summary below by choosing no more than three words from the passage. Remember to write the answers on the Answer Sheet.　　Questions 1-5 are based on the following passage.The City of the Future　　What will city life be like in the future? Some people think that life in the cities is going to be horrible. They predict that cities will become more and more crowded. As the number of people increases, there will be less space for each person. This overcrowding will cause other problems—more crime, dirtier streets, and worse problems with traffic than we have now. How will people find enough drinking water, energy (such as gas and electricity), and housing? Because life will be hard, people who live in cities will worry more, and they may become sick. For these reasons, some say that nobody will want to live in urban areas.　　How can we solve such problems as overcrowding, crime, and traffic? In some cities, thousands of people are already sleeping in the streets because there is so little suitable housing—and because rents are so high. The crime rate isn’t going down. Instead, it is increasing so fast that many people are afraid to go out at night. Traffic is also getting worse. More and more often, traffic jams are so bad that cars don’t move at all for several blocks. These urban problems have been getting worse, not better, so many people see no hope for the future of the city.　　Los Angeles, California, for instance, has no subway system and the buses are slow. Instead, most commuters drive many miles from their homes to work. Many of these drivers spend several hours each day on busy freeways. New York, by contrast, has a mass transit system—buses, commuter trains, and subways. Because the public transportation is crowded and dirty, however, many people drive private cars, and the traffic jams are worse than in Los Angeles.　　On the other hand, some cities have clean, fast, and pleasant public transportation systems. In Paris, France, and Toronto, Canada, for example, anyone can use mass transit to move quickly from one part of the city to another.　　The disadvantages of any modern city are not unique to that city—that is, cities all over the world have to solve the problems of traffic jams, crime, housing, energy, drinking water, and overcrowding. Yet many cities have found answers to one or more of these difficulties. Some European cities, such as Stockholm, Sweden, or London, England, have planned communities that provide people with apartments, jobs, shopping centers, green space, entertainment, and transportation. Many U.S. cities are rebuilding their downtown areas. Urban planners can learn from one another. They can try solutions that have been successful in other parts of the world.　　Summary:　　Some people think that life in the cities is going to be horrible. They say that cities will become more and more crowded and many other problems will be caused by this 　1　Due to the hard life, people do not want to live in 　2　These urban problems such as overcrowding, crime and traffic have been getting worse, so many people 　3　for the future of the city. However, these disadvantages of any modern city are not unique to that city. All the cities all over the world must solve the problems and fortunately, many of them have found answers to one or more of these difficulties. For example, 　4　or London has planned communities providing people with apartments, jobs and so on. Besides, many U. S. cities 　5　In a word, solutions that have been successful in a place should be adopted and tried in another place.

Pollution is a problem because man, in an increasingly populated and industrialized world, is upsetting the environment in which he lives. Many scientists maintain that one of man’s greatest errors has been to equate growth with advancement. Now “growth” industries are being looked on with suspicion in case their side effects damage the environment and disrupt the relationship of different forms of life. The growing population makes increasing demands on the world’s fixed supply of air, water and land. This rise in population is accompanied by the desire of more and more people for a better standard of living. Thus still greater demands for electricity, water and goods result in an ever increasing amount of waste material to be disposed of.The problem has been causing increasing concern to living things and their environment. Many believe that man is not solving these problems quickly enough and that his selfish pursuit of possessions takes him past the point of no return before be fully appreciates the damage.

Practice 13　　(1) Actually, the world’s birth rate is falling. But so is death rate, as medical advances have made it possible for man to live longer than before. Such advances have also reduced baby death rate. (2) Unless population growth is reduced, the world population may reach l2 billion in a century. Is the earth capable of providing a good life for so large a population?

As a result of the epidemic of AIDS in Africa, _____.

Pollution　　1)Pollution is a problem because man, in an increasingly populated and industrialized world，is upsetting the environment in which he lives. 2) Many scientists maintain that one of man's greatest errors has been to equate growth with advancement. 3) Now “growth” industries are being looked on with suspicion incase their side effects damage the environment and disrupt the relationship of different forms of life. 4) The growing population makes increasing demands on the world’s fixed supply of air, water and land. 5) This rise in population is accompanied by the desire of more and more people for a better standard of living. 6) The problem has been causing increasing concern to living things and their environment.

Practice 5　　Water is essential for life. Yet many millions of people around the world face water shortages. Many millions of children die every year from water-borne diseases. And drought regularly afflicts some of the world’s poorest countries.　　The world needs to respond much better. We need to increase water efficiency, especially in agriculture. We need to free women and girls from the daily chore of hauling water. We must involve leaders of countries in decision-making on water management. We need to make sanitation a priority. This is where progress is lagging most. And we must show that water resources need not be a source of conflict. Instead, they can be a catalyst for cooperation.　　Significant gains have been made. But a major effort is still required. Our goal is to meet the internationally agreed targets for water and sanitation by 2015, and to build the foundation for further progress in the years beyond.　　This is an urgent matter of human development, and human dignity. Together, we can provide safe, clean water to the entire world’s people. The world’s water resources are our lifeline for survival, and [or sustainable development in the 21st century. Together, we must manage them better.

Pollution and Ecocrisis　　The problem of pollution is also of great social concern. Continued population increase, accompanied by a rise in the level of living standards, not only threatens to exhaust American resources but pollutes the environment to such an extent that production in the thickly settled area is impossible without damaging the health of the local residents.　　Smog, once an urban annoyance, is now recognized as a health risk, and the automobile has been pinpointed as the principal culprit. Heavy industries have been blamed for river, soil, air, noise and visual pollutions. DDT and other chemical remedies have been doing more ecological harm than the good that they may have brought along.　　Several decades ago, Americans dumped raw sewage into rivers and many industrial plants are now still dumping chemical pollutants into lakes, rivers and oceans. Oceans used to be and are still being considered to be a reserve of seafood. Today, after the oceans have become the home of all pollutants, this use of the oceans is being reduced at an alarming rate.　　The worst pollution threat is concentrated in and near large cities. There the people-made pollutants increasingly surpass the ability of air and water to dilute (冲淡；稀释) the contaminants (污染物) to safe levels. The natural ecological cycle depends on plants, which absorb some pollutants and release oxygen to the air. But near large cities, natural vegetation becomes scarce, and introduced trees, ornamental shrubs and gardens are far from adequate in absorbing motor vehicle and industrial air pollutants. Finally, some pollutants, most notably atomic waste, may continue to contaminate air, land, and water for thousands of years. Therefore, ecocrisis—ecocatastrophe or ecocide—has been for some time one of the major concerns of not only the ecoactivists and environmentalists, but of many scientists of other fields and the government authorities of many countries as well.　　Last but not least, there is the question of whether the people will eventually be able to solve all these problems. The American continent is a wealthy land inhabited by many able and well-　　educated people. There today, people have originated a life-style which is known to the world as being characteristic of a society of consumption—a life-style based on the prodigal (挥霍浪费的) use of material goods. They are using up many times their share of the earth’s resources at a rate unparalleled in history. And I am sorry to say that this life-style of American has been copied by the people of many developed countries, leading to the greatest problem of the modem world as a whole. So I must ask: Are the Americans apt enough to cooperate with other peoples to prevent over-population, resource exhaustion, the catastrophe of pollution and the wanton waste of wealth — problems which are basic to the solution of many outstanding economic, social and political problems? Only time will tell.

One reason for quick population increase in underdeveloped countries is that ______.