1. 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.
- 答案是C
- 我的问题时怎么解释B的错误？B说需求量上升，可能供不应求所以导致价格下降怎么不对了？
2. The country of Baurisia has, until now, been self-sufficient in both grain and meat. However, with growing prosperity in Baurisia has come a steadily increasing per capita consumption of meat, and it takes several pounds of grain to produce one pound of meat. Therefore, since per capita income in Baurisia is almost certain to rise further but increases in domestic grain production are highly unlikely, Baurisia is soon likely to become an importer of grain.
Which of the following, if true, most seriously weakens the argument?
A. When people increase their consumption of meat, they also tend to increase their consumption of grain.
B. The per capita consumption of meat in Baurisia is roughly the same across all income levels.
C. Per capita consumption of meat has not increased substantially in recent years in those countries from which Baurisia is likely to import meat.
D. It is more economical for Baurisians to import meat than grain.
E. During Baurisia's years of growing prosperity, the country's population has remained relatively stable.
答案是D，不懂B，B肉的人均消费量不随收入水平的变化，就是说人均收入就算变了，也不会影响肉的人均消费量，那这不是削弱了题干的since per capita income in Baurisia is almost certain to rise further，Baurisia is soon likely to become an importer of grain？？？？？？？
谢谢解答！
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发表于 2017-9-22 20:40:01
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