[求助]OG-153

OG-153 题干：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.

这道题做了第二遍还是做错，主要是因为我没理解第二句话尤其是括号中的意思，请斑主和各位高手指点一下。

然而，使太阳能比较经济的下限（即每桶油需要增加的价格，以使太阳能工厂能够比用石油燃料的工厂更有经济效益）没有变，还是XX元。

第一次发问这么快就得到回复，CD真是个实用的好东东！谢谢lukrenee版主！

经你指点，这道题已经顺利拿下。