20. Currently, the largest hydropower station in the world that has been built is $\qquad$
A. Gezhouba Hydropower Station
B. Sanmenxia Hydropower Station
C. Itaipu Hydropower Station
D. Three Gorges Hydropower Station
【Answer】D
【Analysis】The world-famous Three Gorges of the Yangtze River is located at the transition from the second to the third step of China's terrain, with rapid water flow and extremely rich hydropower resources. The Three Gorges Dam, also known as the Three Gorges Water Conservancy Project or the Three Gorges Project, is situated in the Xiling Gorge section of the Yangtze River within the territory of Yichang City, Hubei Province, China. It forms a cascade power station with the Gezhouba Hydropower Station downstream. The entire project consists of a river-blocking dam, a large hydropower station, and navigation facilities, and was completed in 2009. With a total installed capacity of 22.5 million kilowatts, it far exceeds the Itaipu Hydropower Station in Brazil, which ranks second in the world. The Three Gorges Dam is the largest hydropower station in the world and the largest engineering project ever constructed in China, with comprehensive benefits including flood control, power generation, navigation, aquaculture, water supply, irrigation, and tourism.