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  3. As the cost of gas and oil for home heating has gone up, many Americans have switched from these fuels to wood for heating their

As the cost of gas and oil for home heating has gone up, many Americans have switched from these fuels to wood for heating their

admin2009-02-10  85
问题      As the cost of gas and oil for home heating has gone up, many Americans have switched from these fuels to wood for heating their homes. In 1973, approximately 200,000 wood-burning stoves, intended for home use, were sold in the United States; by 1979, this figure had reached one million; and by the end of 1981, there were as many as seven million home-owned wood-burning units in operation in the U. S.
     In addition to low fuel bills, many people choose these stoves because their initial cost is very low (the prices range from $ 50 kits to $ 5,000 top-of-the-line models) , and because new technology has made wood fires more efficient, cleaner, and, therefore, safer than ever before.
     One new technological feature of this type is the catalytic(催化) combustor which adds about $100 to $ 200 to the cost of the stove, but which causes much more complete combustion(燃烧) of the wood and therefore burns up more of the pollutants left by incomplete combustion and produces more heat.
     A second cost-saving innovation is a device which agitates the wood, increasing the amount of oxygen that reaches the center of the wood pile, and leading to more efficient combustion. The real advantage of this device is that it allows the owner to make use of cheap sources of wood such as dirty wood chips ( an industrial by-product) that have almost no commercial value, cost as little as $ 20 a ton, and burn very inefficiently in furnaces without an agitator.
Which one of the following is NOT true for the reason why people prefer to buy wood-burning stoves?
选项 A、The initial cost is very low.
B、The fuel costs are cheaper.
C、Wood fires are more efficient, cleaner, and safer than ever before.
D、The wood-burning stoves are more efficient than gas or oil ones.
答案D
解析 文中第二段指出：“many people choose these stoves because their initial cost is very low，and because new technology has made wood fires more efficient，cleaner，and，therefore，safer than ever before，”所以A、C两项可排除，第二段开头就有“In addition to low fuel bills，”加上开头段“As the cost
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