例：An investigation must be launched into the operations of the private group that is training recruits to fight against the Balaland Republic. The U.S. Neutrality Act plainly forbids US citizens from engaging in military campaigns against any nation with which we are not at war. Since no war has been declared between the United States and the Balaland
Republic, we should bring charges against these fanatics, who are in open defiance of the law.
Which of the following, if true, would most weaken the argument above?
首先，读GMAT逻辑题题干，知道这是weaken题。请立刻在脑海中想到答案就是最有效“反对”前提的一个。按此思路，我们就要找到“因为”。
此篇GMAT逻辑题原文的意思：因为：某团体组织人在非战时进行对抗B国的军事训练;并且，法律禁止美国公民在非战争状态下参与对他国的军事对抗行为;所以：该组织应被调查和指控。
GMAT逻辑题解题思路：我们要反对“因为”，那么答案一定要对“因为”的内容进行质疑。由于这里的“因为”有两句，所以为我们筛选质疑哪个“因为”增加了难度。但实际上，我们要质疑的不是法律，所以，第二个因为就可以排除在答案之外。因此，你就要去在5个选项中找存在对第一个因为产生质疑的选项。
答案：a. The Balaland
Republic is currently engaged in a bloody and escalating civil war.
b. Diplomatic relation between US and Balaland were severed last year.
c. The recruits are being trained to fight only in the event the US goes to war against Balaland.
d. The training of recruits is funded not by US citizens, but rather by a consortium of individuals from abroad.
e. Charges cannot be brought against the private group that is training the recruits unless an investigation is first launched.
很显然，c恰好是用“该团体只是训练人员已备战时使用，并非是在非战争状态下对B国进行军事对抗”反对了第一个因为，所以直接选择就好了。
当然，我们最好也去看一下其他GMAT逻辑题的选项，以防备自己的疏漏。a\b选项不能质疑，反而使支持，c在文章中没提到，e和第一个因为不相干。而且原文第一句就说了是investigation，并没有错。因此，只有c正确。
GMAT逻辑试题的解法林林总总，不过用因果联系的方法解题也是很迅速的，这种GMAT逻辑的解法在很多场合很奏效，这样的方法大家也是可以参考运用到GMAT考试中的其他环节的。
