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Technologicalimprovements and reduced equipment costs have made converting solar energy directlyinto electricity far more cost-efficient in the last decade. However, thethreshold of economic viability for solar power (that is, the price per barrelto which oil would have to rise in order for new solar power plants to be moreeconomical than new oil-fired power plants) is unchanged at thirty-fivedollars. Whichof the following, if true, does most to help explain why the increasedcost-efficiency of solar power has not decreased its threshold of economicviability? A. The cost of oil has fallendramatically. B.The reduction in the cost of solar-power equipment has occurred despiteincreased raw material costs for that equipment. C. Technological changes have increasedthe efficiency of oil-fired power plants. D. Most electricity is generated bycoal-fired or nuclear, rather than oil-fired, power plants. E.When the price of oil increases, reserves of oil not previously worthexploiting become economically viable. 答案：C题干分析:过去十年,技术进步和设备降价让太阳能转变为电能更加便宜.然而,太阳能 EV的门槛(就是相对于油涨价,每个太阳能厂的电池要比燃油厂的便宜)仍然是 35美元.以下哪个选项最能帮助解释为什么性价比增加的太阳能没有降低他的 EV门槛.
A 油价大跌.如此一来,门槛降低. B 尽管设备原材料增加,太阳能设备费用仍然减少.门槛降低. C 燃油厂效率增高.门槛高了. D 无关 E 油价上升,原来不好开采的石油业可以考虑开采了.这样可能导致油价更高,门槛低
C 难度:三星解题关键 : 括号里的话比较绕,只要理解个意思 ,就是门槛是相对的东西,太阳能厂自己高效了,还有考虑它对手-燃油厂的效率是否也增高了.假设太阳厂产电便宜了,而燃油长由于沙特国王高兴全部赠送原油导致燃油电价狂跌,那么估计大家都不会去买太阳能厂产的电,这一行就做不下去了.
答案选C。对个对于门槛的解释看了中文我还是不太懂。然后像A和E，一个油价大跌，一个油价升高，但门槛都是降低，为什么？然后我觉得既然C可以，为什么A不可以呢？A和C都是燃油厂的工作成本降低了啊。
求大神解救。
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发表于 2013-9-29 14:18:57
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