请教逻辑题T-4-Q2

legnawen

T-4-Q2
Twenty years ago, Balzania put in place regulations requiring operators of surface mines to pay for the reclamation of mined-out land. Since then, reclamation technology has not improved. Yet, the average reclamation cost for a surface coal mine being reclaimed today is only four dollars per ton of coal that the mine produced, less than half what it cost to reclaim surface mines in the years immediately after the regulations took effect.

Which of the following, if true, most helps to account for the drop in reclamation costs described?

A.    Even after Balzania began requiring surface mine operators to pay reclamation costs, coal mines in Balzania continued to be less expensive to operate than coal mines in almost any other country.
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.
C.    Mine operators have generally ceased surface mining in the mountainous areas of Balzania because reclamation costs per ton of coal produced are particularly high for mines in such areas.
D.    Even after Balzania began requiring surface mine operators to pay reclamation costs, surface mines continued to produce coal at a lower total cost than underground mines.
E.    As compared to twenty years ago, a greater percentage of the coal mined in Balzania today comes from surface mines.

我选的是D 找不到答案在哪里？请教

rudder86

我觉得应该是选C吧。

20年前，Balzania地区实施了需要为surface mines支付reclamation的法规，然后给了一堆信息之后，但是发现，现在分摊到每吨煤上的reclamation cost比法规生效时的一半还少。从这里可以推出surface mines开采所占总开采的比例变小了，或者煤的价格增加了。
再看选项，B说自从法规生效以来，煤作为燃料的使用较少了。
C说煤老板逐渐停止了在山区的surface mining，因为这些地方产的煤，需要支付较高的reclamation costs，也就是变相的说reclamation costs在减少，正确。
D说法规实施之后，surface mines开采的状态在持续，似乎看不出有变化。
E说跟20年前比，Balzania地区更多的煤来自surface mines，推出reclamation cost所占每吨煤的比重应该是上升，而不是下降，不对。
A项貌似跟D差不多，没有提到20年前和现在的变化。而文章的答案应该是一个提到前后有变化的选项。

gabriel_djh

分摊到每吨煤上的reclamation cost比法规生效时的一半还少-----》【这里可以推出surface mines开采所占总开采的比例变小了，或者煤的价格增加了】
意思是说，本来费用应该增加的【立法之后】，但是实际上 每吨的花费变少了{数量*单价=总cost} 有可能
1。数量↓2.现在的媒价格↓↓↓↓→→→→→
问题问的是‘ 帮助drop in reclamation costs described?’
↓↓↓reclamation costs
C中说停止开采了，不开发了。那个地方不受发展了，为了要发展→→所以帮助了减少reclamation costs    才有人来开采煤矿

这理解对么？

sbjqbS

我觉得是这么理解的：
因为mountainous areas of Balzania 的reclamation cost比其他煤矿的都要高，因此只要这些煤矿关闭了，那么平均数肯定是下降了的，这有点数学原理的感觉：4,5,6,7,8的平均数的6，只要去掉比6大的数，那么剩下的数的平均值就比6要小了，例如去掉8， 剩下的4个数的平均数九时5.5<6

piacia

我觉得这道题如果没有reclamation cost 的常识不太好解答， 我答题的时候就认为relaimation cost 每个矿都是一样的的呢，没有高低之分。。

但是题目中给了一个句子 the average reclamation cost for a surface coal mine being reclaimed today is only four dollars per ton of coal that the mine produced

里面用了average, 可以推断应该是不同的， 但考试一紧张估计还是会看漏

handapink

非常同意~~

seuhongkai

我是这样理解这个c的，就是被迫离开市场的都是高成本的，留下的都是低成本的，所以成本降低了