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?
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
我觉得因为加强题只要加强结论成立的可能性就可以,所以原结论的逆命题和逆否命题都可以成为答案,而假奇迹私服设题是一个必要条件,所以要保证结论一定能成立,所以只能用逆否命题了是吗? 还有如果是推论题,即MUST BE TURE这种情况下,如果题目中的fact是有人在飞机上使用手机,飞机的仪表被干扰,它的一个推论也只能是逆否命题,即飞机的仪表没有被干扰,因为没有人在飞机上用手机,而不能是逆命题,即没有人在飞机上用手机,飞机的仪器没有被干扰,这样理解对吗?