3 道ＯＧ，看看嘛！og-96,og-131,og-153

swlfx

谢谢斑竹的精彩回答。

fox2fox

我对此题的一点理解：【只有每桶油价比现实油价上涨35刀，才能使太阳能电厂的经济效率高于燃油发电厂，虽然新技术使得太阳能技术的效率不断提升，但35刀这个阀值却一直未被降低或突破，理由只有一个：燃油的效率也被同步等比的提高了】

ashtreeliu

后面的new-fired power plant表面火力发电的成本也降了，注意这个new
括号里面的意思就是解释这个threshold of economic viability，搞不清什么也无所谓，意思就是后面的35刀

前面说solar power的成本在近几十年也降下来了

但是solar和fired之间的差距还是35刀

答案很显然C，增加了oil-fired的利用率就是降低了油的成本，结果太阳能虽然降价了，但是比起oil还是还是贵了

鸢儿gmat

threshold那道题：
摘自manhattan论坛：
The threshold of economic viability is the price-per-barrel of oil at which electricity from solar power is about as expensive as is electricity from a new oil-fired plant. As the price of electricity from solar power comes down, we naturally expect that the threshold will come down.


C is the right answer because it explains that the cost of electricity from a new oil-fired plant is not determined solely by the cost of the oil that that plant burns.

the cost efficiency of solar has increased but at the same time the efficiency of oil has also increased.