Water problems in the future will become more intense and more complex. Our increasing population will tremendously increase urban wastes, primarily sewage. On the other hand, increasing demands for water will decrease substantially the amount of water available for diluting wastes. Rapidly expanding industries which involve more and more complex chemical processes will produce large volumes of liquid wastes, and many of these will contain chemicals which are poisonous. To feed our rapidly expanding population, agriculture will have to be intensified. This will involve ever-increasing quantities of agriculture chemicals. From this, it is apparent that drastic steps must be taken immediately to develop corrective measures for the pollution problem.
　　There are two ways by which this pollution problem can be lessened. The first relates to the treatment of wastes to decrease their pollution hazard. This involves the processing of solid wastes "prior to" disposal and the treatment of liquid wastes, or effluents (废料) , to permit the reuse of the water or best reduce pollution upon final disposal.
　　A second approach is to develop an economic use for all or a part of the wastes. Farm manure is spread in fields as a nutrient (养料 ) or organic supplement. Effluents from sewage disposal plants are used in some areas both for irrigation and for the nutrients contained. Effluents from other processing plants may also be used as a supplemental source of water. Many industries, such as meat and poultry processing plants, are currently converting former waste production into marketable byproducts. Other industries have potential economic uses for their waste products.

　　26. The purpose of this passage is_______.
　　A. to warn the reader of the dwindling water supply
　　B. to explain industrial uses of water
　　C. to acquaint the reader with water pollution problems
　　D. to demonstrate various measures to solve the pollution problem
 
　　27.Which of the following points is not included in the passage?
　　A. Industrial development includes the simplification of complex chemical processes.
　　B. Diluting wastes needs certain amount of water.
　　C. Demands for water will go up along with the expanding population.
　　D. Intensive cultivation of land requires more and more chemicals.

　　28. The reader can conclude that_______.
　　A. countries of the world will work together on pollution problems
　　B. byproducts from wastes lead to a more prosperous marketplace
　　C. science is making great progress on increasing water supplies
　　D. some industries are now making economic use of wastes

　　29.The author gives substance to the passage through the use of_______.
　　A. interviews with authorities in the field of water controls
　　B. opinion and personal observations
　　C. definitions which clarify important terms
　　D. strong argument and persuasions

　　30.The words "prior to" (Para. 2) probably mean_______.
　　A. after B. during
　　C. before D. beyond

　　答案：26. C 27. A 28. D 29. B 30. C