关于“木川”的疑问及八戒个人逻辑小结！[原创]

紧急求助版主和大牛－关于逻辑的思维方向
困惑！！！费费在讲逻辑演绎题中的削弱时说过，反对就是反对结论，而且我还记得他说过不能反对原因。这两天我在网上down了网友的钱勇强的逻辑笔记，说反对一定是反对原因。原话是这样的：
读者应当注意到反对的重点在于前提，达到的效果一定使结论不对，不论是直接反对原因还是对前提事实做出另一种说明都是从前提入手，所以考生应该在找出并理解前提和结论后，把解题重点放在前提中。
我想肯定很多大牛对此不屑，只要是能够作对，管他是反对结论还是反对前提，都没错。可是本人实在愚钝，要是脑子转不过这个筋，我心里就七上八下。比如有一道题是这样：
Doctors in Britain have long suspected that patients who wear tinted eyeglasses are abnormally prone to depression and hypochondria. Psychological tests given there to hospital patients admitted for physical complaints like heart pain and digestive distress confirmed such a relationship. Perhaps people whose relationship to the world is psychologically painful choose such glasses to reduce visual stimulation, which is perceived as irritating. At any rate, it can be concluded that when such glasses are worn, it is because the wearer has a tendency to be depressed or hypochondriacal。

23. Each of the following, if true, weakens the argument EXCEPT:

(A) Some people wear tinted glasses not because they choose to do so but because a medical condition of their eyes forces them to do so.

(B) Even a depressed or hypochondriacal person can have valid medical complaints, so a doctor should perform all the usual objective tests in diagnosing such persons.

(C) The confirmatory tests were not done for places such as western North America where the usual quality of light differs from that prevailing in Britain.

(D) Fashions with respect to wearing tinted glasses differ in different parts of the world.

(E) At the hospitals where the tests were given, patients who were admitted for conditions less ambiguous than heart pain or digestive distress did not show the relationship between tinted glasses and depression or hypochondria

看这几道题，答案是其次，关键是看看怎么反对。A和D是属于他因反对。而B和D确实是置疑了前提，请问大牛，这种说法对么？那么就是说费费说得不对了？还是我记错了？
因为在错题过程中，迷惑选项特别多，所以我觉得搞清楚答案的方向和ETS的思维很关键。
强烈请求大牛和版主的指导。
感谢。

og逻辑的第14道题我实在不理解，有那位高手师傅可以帮忙解释一下，我的邮箱ffanghua(A) hotmail.com,非常感谢了