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Passage One Just 30 years ago some 700 million people lived in cities. Today the number stands at 1,800 million, and by the end of the century it will be up to 3,000 million-more than half the world’s estimated population. By the year 2000 an estimated 650 million people will crowd into 60 cities of five million or more-three quarters of them in the developing world. Only a single First World city-metropolitan Tokyo, which will have 24 million people-is expected to be among the global top five; London, ranked second in 1950 with ten million people, will not even make 2000’s top 25. In places where rates of natural population increase exceed three percent annually-meaning much of the Third World-that alone is enough to double a city’s population within 20 years. But equally powerful are the streams of hopeful migrants from the countryside. What faces and confuses urban planners is the huge scale of these trends. There have never been cities of 30 million people, let alone ones dependent on roads, sewer and water supplies barely adequate for urban areas a tenth that size. And the flood of new arrivals in swelling Third World cities far overtakes the supply of jobs-particularly as modem industries put a premium on technology rather than manpower. So it will be virtually impossible to find permanent employment for 30 to 40 percent of the 1,000 million new city inhabitants expected by the year 2000. Despite the terrible conditions that the city newcomers face, their numbers are growing at rates as much as twice that of the cities themselves-and every step taken to improve their living conditions in the slums only attracts more migrants. According to the last paragraph, all of the following are true EXCEPT that ______
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Passage Three Demands for stronger protection for wildlife in Britain sometimes hide the fact that similar needs are felt in the rest of Europe. Studies by the Council of Europe, of which 21 counties are members, have shown that 45 percent of reptile species and 24 percent of butterflies are in danger of dying out. European concem for wildlife was outlined by Dr Peter Baum, an expert in the environment and natural resources division of the council, when he spoke at a conference arranged by the administrators of a British national park. The park is one of the few areas in Europe to hold the council’s diploma for nature reserves of the highest quality, and Dr Peter Baum had come to present it to the park once again. He was afraid that public opinion was turning against national parks, and that those set up in the 1960s and 1970s could not be set up today. But Dr Baum clearly remained a strong supporter of the view that natural environments needed to be allowed to survive in peace in their own right. "No area could be expected to survive both as a true nature reserve and as a tourist attraction," he went on. ① The short-sighted view that reserves had to serve immediate human demands for outdoor recreation should be replaced by full acceptance of their importance as places to preserve nature for the future. "We forget that they are the guarantee of life systems, on which any built-up area ultimately depends," Dr Baum went on. "We could manage without most industrial products, but we could not manage without nature. However, our natural environment areas, which are the original parts of our countryside, have shrunk to become mere islands in a spoiled and highly polluted land mass.\ In Dr Baum’s opinion, the view that a nature reserve should serve as a tourist attraction is______
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Passage Four Scientists are closely concerned with the structure of buildings and with the quality of building materials. The World Health Organization(WHO) observes that the introduction of air conditioning and energy conservation measures have been accompanied by growing problems of indoor air quality. Some pollutants arise from insulation products, some from moving cars, and others from modern housing materials. As many Europeans spend up to 90% of their lives in buildings, the health effects of the indoor climate are very important. Some construction materials, including fiberboard, insulation foams and certain glues for man-made wood floor boards, for example, gives out organic products such as formaldehyde(甲). Heat and humidity increase the release of formaldehyde and the gas seriously harms the eyes. Paint, lacquer, etc. can also release dangerous gas into indoor air. Construction materials can cause serious damage, especially when they contain asbestos(石棉). Asbestos is naturally present in rock formations worldwide. It belongs to a family of mineral substances composed of solid, non-combustible fiber. These properties make asbestos a highly sought-after construction material. As early as 1931, however, public health officers in the United Kingdom revealed the connection between breathing in asbestos dust and such diseases as lung cancer. The land on which a building is sited may also contribute to pollution. Some kinds of granite or similar rocks contain traces of radium(/~i ). As it breaks down, this naturally radioactive element produce some kind of radioactive gas that goes through tiny cracks in walls, floors and building materials, and makes its way into the building and the rooms. The better the homes are insulated, the more is the dangerous gas in indoor air. The main effect of this dangerous gas on health is to increase the risk of lung cancer. Why should we be careful about the land on which a building is to be sited
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