【答案解析】Cities have been destroying the environment around them and have paid a lot for it. Scientists discover that an old city bas been buried under the ground for thousands of years just because it was flooded by deforestation. In addition, a city will bring many problems to citizens. It is estimated that by 2050, the number of people in towns will have exceeded the number of people in rural areas for the first time in human history. Humamkind's future will depend largely on the conditions of cities. The living quality of the next few generations and the opportunities to solve the domestic and international conflicts will depend on whether the government of every nation can find solutions to controlling the excessively rapid development of cities.