本世纪中,世界城市已扩大至人类历史上空前的规模。到2000年,人口统计学家预测东京、墨西哥城和圣保罗每个城市人口超过2000万,现今有14个大城市人口超过1000万,到本世纪末,预测马尼拉、开罗、雅加达、德里、拉各斯、卡拉奇和达卡也将加入这个名单。在一些发展中国家的城市里,儿童和青少年超过人口的一半。除了如Robert Legget之书《城市和地质》是著名的之外,大多数有关城市的专门文 In the middle of this century, the cities of the world have expanded to an unprecedented scale in human history. By the year 2000, demographers predicted that the population of each city in Tokyo, Mexico City, and São Paulo exceeded 20 million. Today, there are 14 large cities with a population exceeding 10 million. By the end of this century, it is predicted that Manila, Cairo, Jakarta, Delhi, Lagos Karachi and Dhaka will also join this list. In some developing country cities, children and adolescents exceed half of the population. In addition to the famous book “City and Geology”, such as Robert Legget, most of the articles on urban