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美国大陆约一半面积是干旱、半干旱地区,在行政区划上,西部的十七个州中有的全部州或州的一部分都位于这个范围。美国西部近八十余年来,进行了大规模的水资源开发与调水工程。这些工程主要集中于加利弗尼亚州与亚利桑那州。一位丹
About half of the continental United States is arid and semi-arid, and in administrative divisions, some or all of the seventeen states in the west are located in this area. Nearly 80 years in the western United States conducted a large-scale water resources development and water transfer project. These projects are mainly concentrated in California and Arizona. One Dan