Although dams can be built to store water for agricultural use in dry areas and dry seasons, the costs of water redistribution(重新分配)are very high.Not only is there the cost of the engineering itself, but there is also an environmental cost to be considered.Where valleys(山谷)are flooded to create dams, houses are lost and wildlife homes destroyed.Besides, water may flow easily through pipes to fields, but it cannot be transported from one side of the world to the other.Each country must therefore rely on the management of its own water to supply its farming requirements.

　　This is particularly troubling for countries with agricultural industries in areas dependent on irrigation (灌溉)．In Texas, farmers' overuse of irrigation water has resulted in a 25% reduction of the water stores.In the Central Valley area of southwestern USA, a huge water engineering project provided water for farming in dry valleys, but much of the water use has been poorly managed.

　　Saudi Arabia's attempts to grow wheat in desert areas have seen the pumping of huge quantities of irrigation water from underground reserves.Because there is no rainfall in these areas, such reserves can only decrease, and it is believed that fifty years of pumping will see them run dry.

　　1．From the first two paragraphs we learn that________.

　　A．much of the world's water is available for use

　　B．people in high rainfall countries feel lucky

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