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?
理解题意:
1. threshold是门槛临界值的意思,这里理解成临界值肯定更贴切。
2. 括号里面,that is,that指代的是括号前面的一坨坨,是个of 短语,所以中心词是of 前面的东西,所以,that is后面解释的是threshold,临界值,而不是econ viability,也不是solar power。threshold is the price per barrel。然后后面一坨坨修饰这个price。 oil would have to rise to which (price=threshold) in order for new solar power plants to be more economical than new oil-fired power plants. 太阳能经济可行性的临界值就是一个油价,这个油价上升到临界值为了新太阳能工厂 更加经济比新 燃油工厂。