有个关于逻辑思路的问题想请教大家一下-无因无果和无果无因，急急急

Joseph_lin

这样吧，我说了更明白点儿吧。

题中的结论是有人在飞机上使用手机，飞机的仪表被干扰

1，推论题：A 没有人在飞机上使用手机，飞机的仪表没有被干扰 B 飞机仪表没有被干扰，因为没有人在飞机上用手机
2，加强题：A 没有人在飞机上使用手机，飞机的仪表没有被干扰 B 飞机仪表没有被干扰，因为没有人在飞机上用手机
3，假设题：A 没有人在飞机上使用手机，飞机的仪表没有被干扰 B 飞机仪表没有被干扰，因为没有人在飞机上用手机

如果是你，你会怎么选？注意，可以A B都选，也都可以A B都不选。

Joseph_lin

这里还有道题目，或许能说明点儿问题
22.   In humans, ingested protein is broken down into amino acids, all of which must compete to enter the brain. Subsequent ingestion of sugars leads to the production of insulin, a hormone that breaks down the sugars and also rids the bloodstream of residual amino acids, except for tryptophan, Tryptophan then slips into the brain uncontested and is transformed into the chemical serotonin, increasing ht brain’s serotonin level. Thus sugars can play a major role in mood elevation, helping one to feel relaxed and anxiety-free.

Which one of the following is an assumption on which the argument depends?
(A) Elevation of mood and freedom from anxiety require increasing the level of serotonin the brain.
(B) Failure to consume foods rich in sugars results in anxiety and a lowering of mood.
(C) Serotonin can be produced naturally only if tryptophan is presented in the bloodstream.
(D) Increasing the level of serotonin in the brain promotes relaxation and freedom from anxiety.
(E) The consumption of protein-rich foods results in anxiety and a lowering of mood.

答案是D，我看了下Critical Bible上的解释就是说A不行的原因就是把increase in serotonin当成了必要条件，而原文是充分条件。但是我觉得如果我对A取非，就是Elevation of mood and freedom from anxiety doesn't require increasing the level of serotonin the brain,那么不也削弱了原文的结论Increasing the level of serotonin in the brain promotes relaxation and freedom from anxiety了吗，这样应该也可以吧？？？
如果我这里再多出2个选项：F No Elevation of mood and freedom from anxiety, No increasing the level of serotonin the brain 和 G No increasing the level of serotonin the brain, No Elevation of mood and freedom from anxiety,那么按照上面的充分和必要的说法的话，是不是也只有F对了呢？