单选题 If a mechanical aerator is installed in a fish pool, the water in the pool can be properly aerated. So, since John's fish pool does not have a mechanical aerator, it must be that his pool is not properly aerated. Without properly aerated water, fish cannot thrive. Therefore, any fish in John's pool will not thrive.
Which one of the following arguments contains an error of reasoning that is also contained in the argument above?

A、 If alum is added to pickle brine, brine can replace the water in the pickles. Therefore, since Pauls does not add alum to her pickle brine, the water in the pickles cannot be replaced by brine. Unless their water is replaced with brine, pickles will not stay crisp. Thus, Paula's pickles will not stay crisp.
B、 If pectin is added to jam, the jam will gel. Without a setting agent such as pectin, jam will not gel. So in order to make his jam gel, Harry should add a setting agent such as pectin to the jam.
C、 If stored potatoes are not exposed to ethylene, the potatoes will not sprout. Beets do not release ethylene. Therefore, if Sara stores her potatoes together with beets, the potatoes will not sprout.
D、 If a carrot patch is covered with mulch in the fall, the carrots can be left in the ground until spring. Without a mulch cover, carrots stored in the ground can suffer frost damage. Thus, since Kevin covers his carrot patch with mulch in the fall, the carrots can safely be left in the ground.
E、 (E) If tomatoes are not stored in a dark place, their seeds sometimes sprout. Sprouted seeds can make tomatoes inedible. Therefore, since Maria does not store her tomatoes in a dark place, some of Maria's tomatoes could be inedible.

【正确答案】 A

【答案解析】[解析] 本题的论证把某一件事成立的一个条件当作了它的一个必要条件来推理，从而得出了不正确的结论。选项(A)中的明矾加入泡菜的盐水只是盐水可以取代泡菜中的水分的一个条件，而非必要条件；而作者在论证中却把它当必要条件来使，显然犯了与本题的题干中的论证相一致的推理错误。(B)、(C)、(D)和(E)四选项一开始提出的某一命题成立的条件都是该命题成立的必要条件，因此它们的推理方式都是正确的。