以下是引用grape262001在2009-1-18 17:03:00的发言:时隔这么多年又把老帖翻出来,真是很不好意思。 但是我还是想要弱弱的问一下,关于这个B选项 B. In the twenty years since the regulations took effect, the use of coal as a fuel has declined from the level it was at in the previous twenty years. 如果B为真的话,那么煤的使用量少了,是不是可以说需求量少了之后,开采量也就随之而少了,那么回填的费用就会减少呢?那么不可以解释题目吗? 所以我再看了众多NN的解答之后,依然对B很疑惑。 请NN指教! 注意:是four dollars per ton of coal 跟总量没关系 不知道lawyer现在何方啊?真是太N了,理解得透,又能解释得清楚!!! |