A、Ways to reduce the costs of building dams. B、Steps to improve water use management. C、Measures to deal with worldwide water sh

The need to feed a growing population is putting much pressure on the world’s supply of water. With 97% of the world’s water too salty to be drunk or used in agriculture, the worldwide supply of water needs careful management, especially in agriculture. Although the idea of a water shortage seems strange to someone fortunate enough to live in a high rainfall country, many of the world’s agricultural industries experience constant water shortages.
    Although dams can be built to store water for agricultural use in dry areas and dry seasons, the costs of water redistribution 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 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. In Texas, farmers’ overuse of irrigation water resulted in a 25% reduction of the water stores. In the Central Valley area of southeastern 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 been 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.
Questions 32 to 35 are based on the passage you have just heard.
32. What is the passage mainly about?
33. What do we learn from the passage?
34. What can be learned from the passage?
35. What is most likely to be discussed next?