练习题：

长江是亚洲最长、世界上第三长的河流。长江流经多种不同的生态系统，是诸多濒危物种的栖息地，灌溉了中国五分之一的土地。长江流域(river basin)居住着中国三分之一的人口。长江在中国历史、文化和经济上起着很大的作用。长江三角洲(delta)产出多达20%的中国国民生产总值。几千年来，长江一直被用于供水、运输和工业生产。长江上还坐落着世界上最大的水电站。

The Yangtze River is the longest river in Asia and the third longest one in the world. Flowing through many different ecosystems, it is the habitat for a whole host of endangered species and irrigates one fifth of the land in China. One third of Chinese population live in the Yangtze river basin. The Yangtze river plays an important role in the history, culture and economy of China and contributes to as much as 20 percent of the Gross National Product of China. It has been used for water supply, transportation and industrial production for several thousand years. Also, on the Yangtze river lies the largest hydropower station in the world.