请教一道逻辑题

最后的战役UID: 3382274

虎平逻辑E2第7题：

Editorial:
Critics of nuclear power complain about the allegedly serious harm that might result from continued operation of existing nuclear power plants. But such concerns do not justify closing these plants;after all, their operation has caused no more harm than that caused by pollution generated by coal-and oil-burning power plants, the most important other sources of energy.

Which of the following is an assumption on which the argument depends?
(A) Existing nuclear power plants should be closed only
if it can be conclusively demonstrated that their continued operation is likely to cause harm more serious than the harm their operation has already caused.
(B) Closing existing nuclear power plants would require greatly increased reliance on coal-and oil-burning power plants.
(C) The harm that has resulted from operation of existing coal-and oil-burning power plants has been significant.
(D) The harm that a nuclear power plant is likely to cause as it continues to operate can be reliably predicted from the past history of nuclear power plants.
(E) The only harm that has resulted from operation of existing coal-and oil-burning power plants has resulted from the pollution generated by these plants.

问的是assumption，我选了B答案是D；
D的理由应该是过去不能推出将来，但我觉得作者在强调has no more harm than...coal-and oil-burning power plants，就选了B。求解释…

compeUID: 3404227

做assumption的题
我们需要找：
conclusion gap（当然也需要找premise）
这题的conlusion很明显：But such concerns do not justify closing these plants;
premise：after all, their operation has caused no more harm than that caused by pollution generated by coal-and oil-burning power plants, the most important other sources of energy.

那么premise和conclusion之间的gap就是：
（1）coal-and oil burning power plant关了，我们核电才关门。
（2）我们说的是事实
明显能选出D（我们说的是事实）

你可以分别negate B选项和D选项，看看是否会影响原结论。不影响的话就是错误选项。

最后的战役UID: 3382274

compe 发表于 2013-4-29 23:13
做assumption的题
我们需要找：
conclusion gap（当然也需要找premise）

明白了，B选项并不是必须的，文章并没说coal-and oil burning power plant是only source，所以可以找其他的来代替。我自己想当然强加了… while D这个gap必须有！
谢谢compe指点!~

compeUID: 3404227

最后的战役 发表于 2013-4-29 23:19
明白了，B选项并不是必须的，文章并没说coal-and oil burning power plant是only source，所以可以找其他 ...

不客气。。
其实都是robin教的