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 ar 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 thar 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.
请解释一下为什么为C，并翻译一下括号内的意思。多谢！作者: hopejie 时间: 2003-12-5 23:51
括号内的意思：为了使新的太阳能工厂比新的燃油工厂更经济的话，每一桶油所长的价格。
文章中说由于技术进步等原因，使得solar energy directly into electricity far more cost-efficient ，但如果有c 的原因的话，那么由于技术进步也increased the efficiency of oil-fired power plants，所以最终的
结果要取决于这两种变化的对比。由于c 的存在可能解释文中的结论。所以c正确。注意这里题中问的是most而不是 must。如果是must 的话还需要有进一步的说明。
上面是我的观点，有什么不同的意见欢迎继续探讨。作者: qiqi 时间: 2003-12-6 10:28
