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昨天被一道逻辑给郁闷了,看了讨论贴更糊涂了,后来终于自己想通了,很得意,一看表3:30 逻辑OG-153 153. Technological improvements and reduced equipment costs have made converting solar energy directly into electricity far more cost-efficient in the last decade. However, the threshold of economic viability for solar power (that is, the price per barrel to which oil would have to rise in order for new solar power plants to be more economical than new oil-fired power plants) is unchanged at thirty-five dollars.
Which of the following, if true, does most to help explain why the increased cost-efficiency of solar power has not decreased its threshold of economic viability?
(A) The cost of oil has fallen dramatically. (B) The reduction in the cost of solar-power equipment has occurred despite increased raw material costs for that equipment. (C) Technological changes have increased the efficiency of oil-fired power plants. (D) Most electricity is generated by coal-fired or nuclear, rather than oil-fired, power plants. (E) When the price of oil increases, reserves of oil not previously worth exploiting become economically viable. 开始选了A,答案是C,后来想通了 这题这样理解比较好: 当油价为35时,太阳能电和火力电价格持平,即: 太阳能cost=35+火力cost,太阳能cost-火力cost=35,当太阳能cost下降时, 等式继续成立,所以火力cost必然下降,这里与油价没有关系。 |