93. 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.

In my view, the reasoning in this argument is that:

On the one hand:

the presence of salt in the food being cookedà salt effectively blocks the microwaves from heating the interiorà The efficiency of microwave ovens in destroying the harmful bacteria frequently found in common foods is diminished

On the other hand:

unsalted food is heated by microwaveà the interior of unsalted food reaches temperatures high enoughà kill bacteria that cause food poisoning A推B，A否推B否？

So , D is the best choice.

黄标部分的两段推理，分明是取非后推理方向还不变？LSAT里不是特别强调A推B不等于A否推B否吗？是不是只有A是B的充要条件时才能如此推？可是原文中怎么看得出充要条件呢

迷惑。。。

谢谢！

不是Ａ否推Ｂ否．直接根据这句话：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．　　得出Ｄ

如果没有这句话，只有第一句话：salt高－－>danger高．是得不到Ｄ：salt低-->danger低的．（这种时候才是Ａ否推Ｂ否）

hope it will help