China is celebrating the completion of the construction of the Three Gorges Dam, the world's largest project that has been a dream of Chinese leaders since the early 20th century. It is 185 meters high and able to produce enough electricity. People have called it an engineering wonder of the world.

　　The Three Gorges Dam, which stretches across the Yangtze River in Central China's Hubei Province, has been completed nine months ahead of schedule, after 13 years of work, and an expenditure (支出) of $25 billion.

　　It was the Chinese Nationalist leader Sun Yat­sen who, in 1919, first conceived (构想) the idea of a giant dam to control the Yangtze's devastating (毁灭性的) annual floods.

　　In recent years, the push to build a dam has been driven by more modern economic considerations. With China's rapidly growing economy, China badly needs more power. The government says the dam will go some way toward solving the country's energy shortage.

　　Environmentalists, however, have suggested that the reservoir that will be created could become a giant cesspool (污水坑), as untreated waste from nearby cities or chemicals from factories build up.

　　Section_ⅠIntroduction & Reading - Pre­reading