[求助] 请教一道逻辑题？

frankliny

The efficiency of microwave ovens in destroying the harmful bacteria frequently found in common foods is diminished by the presence of salt in the food being cooked. When heated in a microwave oven, the interior of unsalted food reaches temperatures high enough to kill bacteria that cause food poisoning, but the interior of salted food does not. Scientists theorize that salt effectively blocks the microwaves from heating the interior.
Which one of the following conclusions is most supported by the information above?
(A) The kinds of bacteria that cause food poisoning are more likely to be found on the exterior of food than in the interior of food.
(B) The incidence of serious food poisoning would be significantly reduced if microwave ovens were not used by consumers to cook or reheat food.
(C) The addition of salt to food that has been cooked or reheated in a microwave oven can increase the danger of food poisoning.
(D) The danger of food poisoning can be lessened if salt is not used to prepare foods that are to be cooked in a microwave oven.
(E) Salt is the primary cause of food poisoning resulting from food that is heated in microwave ovens.

答案：D
C是说加盐增加食物中毒的危险，D是说不加盐减少食物中毒的危险。看不出C 和 D 的根本区别。

hopejie

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frankliny

两位的解释非常漂亮，一下子就懂了，多谢！

hopejie

补充一下：
题中的结论是：因为盐的存在使得微波炉杀死细菌的效率降低了。而D的选项意思是说，如果不放盐的话就可以“The danger of food poisoning can be lessened ”。　我们可以把D理解为原来命题的一个逆否命题。所以正确。

linsonstudy

C是说把盐加到已经煮好的食物，而不是把盐加到食物中再放进微波炉。因为THAT引导的定语从句是FOOD，明白了这一点就很容易理解了！