![]()
GRE逻辑单题是GRE verbal中一种特殊的题型，解题思路和技巧与我们的填空题型、阅读题型是完全没有共通之处，需要同学们额外花时间学习的。
再加之GRE考试改革后，在整场考试中只会考察1道逻辑单题，逻辑单题可以说是非常“鸡肋”的存在了...
这就意味着很多同学在GRE复习中，不会单独抽出整块的复习时间来复习逻辑单题了。因此特别诞生了【1篇学会1类GRE逻辑单题】系列，希望同学们可以利用一些碎片时间结合这一系列去解决逻辑单题~
这次我们来给大家介绍GRE逻辑题当中最核心（没有之一）的题型——削弱题，即Weaken。
常见问法：
Which of the following, if true, most seriously weakens the argument?
削弱：他每天都在努力学习错误的方法。这个选项很好，因为它符合前提（万蜀黍很努力），且会使得他不能考好，即让结论成立可能性降低。· 最常见的（1）寻找新的原因导致原先有待解释的现象，即给出其它解释；· 次常见的（2）在原文给出的解释不成立的情况下，原文有待解释的现象仍然能够出现，即无因有果。削弱：他作弊了；他之前不努力的时候考得也很好。这两个选项都很好，前一个给出了万蜀黍考好的新的解释，而后一个指出在原因没发生的情况下结果也能发生。这种论证通常是基于AB的伴随发生，推出A导致了B，或者A导致C导致B。那么这种情况下，正确的削弱选项会给出AB伴随发生的其它可能解释，比如B导致了A，比如C同时导致AB，当然如果原题是A导致C导致B，那选项还可能是A导致D导致B。总之，就是要为AB为什么能够伴随发生提供除了原文以外的其它可能路径。A drug that is highly effective in treating many types of infection can, at present, be obtained only from the bark of the ibora, a tree that is quite rare in the wild. It takes the bark of 5,000 trees to make one kilogram of the drug. It follows, therefore, that continued production of the drug must inevitably lead to the ibora’s extinction.
Which of the following, if true, most seriously weakens the argument above?(A) The drug made from ibora bark is dispensed to doctors from a central authority.(B) The drug made from ibora bark is expensive to produce.(C) The leaves of the ibora are used in a number of medical products.(D) The ibora can be propagated from cuttings and grown under cultivation.(E) The ibora generally grows in largely inaccessible places.本文属于结果型论证，基于ibora持续被砍，预测ibora会灭绝。
正确选项需要有某种原因可以让ibora被持续地砍，还能不灭绝。所以选D，因为砍下来的ibora还可以继续培养生长，所以砍了也不会灭绝。Journalist: In physics journals, the number of articles reporting the results of experiments involving particle accelerators was lower last year than it had been in previous years. Several of the particle accelerators at major research institutions were out of service the year before last for repairs, so it is likely that the low number of articles was due to the decline in availability of particle accelerators.
Which of the following, if true, most seriously undermines the journalist’s argument?(A) Every article based on experiments with particle accelerators that was submitted for publication last year actually was published.(B) The average time scientists must wait for access to a particle accelerator has declined over the last several years.(C) The number of physics journals was the same last year as in previous years.(D) Particle accelerators can be used for more than one group of experiments in any given year.(E) Recent changes in the editorial policies of several physics journals have decreased the likelihood that articles concerning particle-accelerator research will be accepted for publication.本文属于一般的解释型论证，要解释为什么涉及particle accelerator的论文少了，解释是能够做实验的particle accelerator少了。
正确答案可能最可能采取给出其它解释或无因有果。E完美，因为E提供了它因，杂志的政策改变不利于涉及particle accelerator的论文发表，可以导致该话题论文发表减少。In the Middle Ages, bloodletting was considered beneficial to health and the procedure was used to treat many illnesses, as well as to improve general health. Modern medicine has shown bloodletting to be harmful in treating many of the illnesses for which it was prescribed in the Middle Ages. Yet people who donate blood regularly to blood banks live longer, on average, than those who never donate blood, so bloodletting probably has some beneficial effect.
Which of the following, if true, points to an error of reasoning in the argument?(A) Medieval medical theories assigned a different role to the blood than modern medicine does.(B) Not all of the conditions for which medieval medicine prescribed bloodletting are worsened by the procedure.(C) Bloodletting diminishes a patient’s ability to fight off certain kinds of infection.(D) Many people who donate blood regularly to blood banks do so less frequently in old age than they did when they were younger.(E) People who are not generally healthy are not permitted to donate blood to blood banks.本文属于复杂的解释型论证，要解释献血的人为什么寿命更长，原文给的解释就是献血有益健康。
那我们期望的选项就是给出其它解释，可以是变量X同时导致献血与寿命长，以及可以是因果关系倒置。E就是我们期望的完美答案，它等于就是在说只有健康的人才能献血，也就是说之所以献血的人寿命长，其实献血与寿命长之间没有因果关系，是第三方因素，即健康，同时导致了献血与寿命长。
小小提醒一下！逻辑单题虽然鸡肋，但对于要冲刺V165+的同学是有必要系统性地了解会出现“哪些类题型”，以及每类题型得“本质考点和解题方法”推荐大家去小破站上看我的《解密GRE逻辑单题》公益系列课程，详细讲解了每类逻辑单题的本质考点和相应的解题思路！也欢迎把这么优质的课程安利给周围也在备考GRE的小伙伴！
最后希望同学们都能备考顺顺利利，拿下心仪的目标分数![]()
