摘要
With a warmer global climate and the modernization of cities, overcoming the problem of water is a common issue that many cities around the world have to face. With the development of modern cities, waste water from both families and factories is continuously flow- ing into lakes and rivers. Heavy rains often hit many cities in countries across the world, such as the South of China, Pakistan. Let us enter the Puxi side of Shanghai Expo, where many international cities are showcasing their achievements such as how to control flooding,
