Assumption解题原理：定义结论句之因果关系, 并确认议题焦点(其实这是做CR的一个普适性原则，要说有多普适，只要打开Support和Weaken的页面，你就会发现这句话原封不动的出现在同样的位置...在这吐槽一句：不是我懒= =)
　　* 正确答案标志：
　　- 否定Weaken(排除他因)(>90%)：
　　正确答案的主要子句中，多存在有否定字，Ex: not, no, less, few, seldom…
　　去掉否定字不看，则正确答案可weaken原题结论句。(其实无论有不有否定字，将正确答案取否命题就可以直接weaken原题结论)
　　- 填补缺口(Gap)(10%)：
　　题目：A —>B
　　结论：B —>C
　　答案：A —>C
　　类似上述之关系，正确答案可将A -->B -->C的关系连结。
　　* 错误答案标志：
　　- 补充信息：仅为题干之补充资料，与结论句之因果关系无关。
　　- 转移焦点：转移焦点至题干可能提及，或未曾提及之事物，但与题目议题焦点无关。
　　- 无关比较：
　　与结论句无关之两群体比较
　　有关与无关之两群体比较
　　有关之群体，拆作两子群体比较
　　- 未能排除他因，反而提出证据支持他因
　　- 答案选项违背原题描述
　　- 答案举出证据weaken了题目结论
　　Some Tips：
　　Assumption类型的题目，先当作Weaken类型的来做;若答案选项中发现没有否定字眼时，注意是否为填补缺口类型题目。
　　例题讲解：
　　TN1-Q40:
　　Until now, only injectable vaccines against influenza have been available. Parents are reluctant to subject children to the pain of injections, but adults, who are at risk of serious complications from influenza, are commonly vaccinated. A new influenza vaccine, administered painlessly in a nasal spray, is effective for children. However, since children seldom develop serious complications from influenza, no significant public health benefit would result from widespread vaccination of children using the nasal spray.
　　Which of the following is an assumption on which the argument depends?
　　首先梳理题目条件：
　　(1)现有的医疗条件下，只有注射的流感疫苗，但是打针很痛，小孩不愿意，大人也不愿意孩子去打(吐槽一句：果真是注射在儿身痛在父母心啊有木有)
　　(2)成年人基本上都注射过流感疫苗，但是他们却有可能感染上一种严重的流感并发症(抗体太普遍于是抗药性强的变种横空出世了么)
　　(3)随着科学的发展，一种新型的鼻喷雾型疫苗发明了，而且对小孩子极为有效
　　(4)但是呢，小孩子感染上述严重并发症的病例非常少，近乎没有
　　结论：这种鼻喷雾使得疫苗广泛接种，但是对公共健康的benefit却不显著
　　看完条件和结论，有没有感觉缺了什么东西?所以，这道题是典型的填补gap题目。
　　这道题个人感觉和Solve the discrepancy有些像，既然可以有效预防小孩得流感，为什么还说对公共健康受益不大呢?但是由题目可以知道：小孩子得流感之后不会引发并发症，麻烦不会很大;但是如果大人从小孩那里感染了流感，则会引起严重的并发症，带来很大麻烦。所以，带孩子去打疫苗就成为了从大人自身出发的考虑，因而家长就会积极带孩子去打新疫苗，对公共健康benefit显然会非常大，但这样就削弱了结论。
　　由此可知题目的assumption是小孩得流感和大人得的流感并发症之间并没有联系，因而才会被认为对公共健康benefit不太显著.
　　A. Any person who has received the injectable vaccine can safely receive the nasal-spray vaccine as well.
　　本选项说，能够接种注射疫苗的都能安全接种这种鼻喷雾疫苗，这只能说明新疫苗和老疫苗功效差不多，不能说明新疫苗对公共健康没有特别显著的好处，因而此选项仅仅是作为题干的补充资料，无法断开小孩得流感和大人得的流感并发症之间的联系，因此无关。
　　B. The new vaccine uses the same mechanism to ward off influenza as injectable vaccines do.
　　本选项说，新疫苗在防止流感的机能上和注射疫苗一样。我认为这个选项有些迷惑性，但是这个选项跟A一样，只能说明新老疫苗功效相同，仅仅作为题干补充资料转移焦点，与题目中心论点关系不大。
　　C. The injectable vaccine is affordable for all adults.
　　本选项说注射疫苗所有大人都支付得起，既没有提到新疫苗也没有提到小孩得流感和大人得的流感并发症之间的联系，属于转移焦点，无关。
　　D. Adults do not contract influenza primarily from children who have influenza.
　　正解。本选项说大人不会从小孩那里感染疫苗，直接断开了小孩得流感和大人得的流感并发症之间的联系，填补了gap。反之，如果将这个选项取非的话，即大人会从小孩那里感染，就是直接weaken结论。
　　E. The nasal spray vaccine is most effective when administered to adults.
　　本选项说鼻喷雾疫苗对大人是最有效的，个人觉得这个削弱了题目的结论，既然对大人小孩都这么有效，那么对公共健康应该benefit非常大才对。故而该选项错误。
　　TN6-Q14：
　　Many people suffer an allergic reaction to certain sulfites, including those that are commonly added to wine as preservatives. However, since there are several wine makers who add sulfites to none of the wines they produce, people who would like to drink wine but are allergic to sulfites can drink wines produced by these wine makers without risking an allergic reaction to sulfites.
　　Which of the following is an assumption on which the argument depends?
　　照例还是先梳理题目条件：
　　(1)很多人对某种硫酸盐过敏，包括被广泛加入红酒作为防腐剂的一种硫酸盐
　　(2)但是有的厂商没有在他们制造的酒里面加硫酸盐
　　结论是：想喝酒但是又对硫酸盐过敏的酒友们可以购买上述厂商生产的红酒，这样就不用冒着过敏的危险偷偷喝酒了～
　　由本题来看，它的逻辑链相较于上一题比较完整，至少但看题目并没有很明显的缺失掉某一环，因此，这道题可以归入排除他因型。
　　本题的中心在于酒中的硫酸盐导致过敏，也就是说，这道题的前提是只要制造商不往酒里加硫酸盐，酒里面就不含有。因此，就不能出现以下的可能：酒里面本来就含有导致过敏的硫酸盐。
　　A. These wine makers have been able to duplicate the preservative effect produced by adding sulfites by means that do not involve adding any potentially allergenic substances to their wine.
　　本选项说的是上述厂商可以通过不加入任何的防腐物质来完美重现加入硫酸盐时的防腐效果(也就是：我啥防腐剂都不加，但是照样能保质!神马硫酸盐防腐剂都是浮云!)，算是个非常迷惑的选项，但是还是无法充分说明酒中本来就不含有硫酸盐。而且这个选项很明显属于转移焦点：题目的中心在于过不过敏，而不是防腐问题。
　　B. Not all forms of sulfite are equally likely to produce the allergic reactions.
　　本选项说不是所有的硫酸盐都一样的会导致过敏。题目里已经明确的说了加到酒里作为防腐剂的那一种是会导致过敏的，也就是说，本选项跟酒里含不含过敏硫酸盐会不会导致人家过敏根本就是木有任何关系，不该偷喝酒的人还是不能偷喝。
　　C. Wine is the only beverage to which sulfites are commonly added.
　　本选项说酒是唯一一种广泛加入硫酸盐来防腐的饮品，也就是说，喝酒会过敏的人就乖乖喝其他饮料吧!但是很可惜，这个选项还是无法证明酒里面只要不人工加硫酸盐就一定没有硫酸盐，因而属于题干补充资料，还是无关的那一种。
　　D. Apart from sulfites, there are no substances commonly present in wine that give rise to an allergic reaction.
　　本选项说除了硫酸盐就没有哪种酒里常见的物质会引起过敏的，还是不能说明酒里面没有天然含有的硫酸盐，因而同上一个选项，属于无关的题目补充资料。这个选项跟A一样比较具有迷惑性，大家看到的时候需要小心。
　　E. Sulfites are not naturally present in the wines produced by these wine makers in amounts large enough to produce an allergic reaction in someone who drinks these wines.
　　正解。本选项说上述厂商制造的酒里没有自然存在的硫酸盐，就算自然存在也没有多到可以引起过敏的地步，也就是说，只要不加，里面就没有。另外将这个选项取非的话，就是上述厂商制造的酒里面有自然存在的硫酸盐，还是多到可以引起过敏的程度，会削弱题目的结论。
　　练习：
　　TN7-Q40:
　　Agricultural societies cannot exist without staple crops. Several food plants, such as kola and okra, are known to have been domesticated in western Africa, but they are all supplemental, not staple, foods. All the recorded staple crops grown in western Africa were introduced from elsewhere, beginning, at some unknown date, with rice and yams. Therefore, discovering when rice and yams were introduced into western Africa would establish the earliest date at which agricultural societies could have arisen there.
　　Which of the following is an assumption on which the argument depends?
　　A. People in western Africa did not develop staple crops that they stopped cultivating once rice and yams were introduced.
　　B. There are no plants native to western Africa that, if domesticated, could serve as staple food crops.
　　C. Rice and yams were grown as staple crops by the earliest agricultural societies outside of western Africa.
　　D. Kola and okra are better suited to growing conditions in western Africa than domesticated rice and yams are.
　　E. Kola and okra were domesticated in western Africa before rice and yams were introduced there.
　　TN16-Q38:
　　Because it was long thought that few people would watch lengthy televised political messages, most televised political advertisements, like commercial advertisements, took the form of short messages. Last year, however, one candidate produced a half-hour-long advertisement. During the half hour the advertisement was aired, a substantial portion of the viewing public tuned into the advertisement. Clearly, then, many more people are interested in watching lengthy televised political messages than was previously thought.
　　Which of the following is an assumption on which the argument depends?
　　A. The candidate’s ratings improved significantly as a result of the half-hour-long political advertisement.
　　B. Political advertisements have become increasingly influential in determining voters’ decisions at the polls.
　　C. Many people would appreciate the opportunity to become better acquainted with political candidates’ views on current political issues.
　　D. Most people who are interested in political issues watch television regularly.
　　E. Most of the viewers who tuned in to the candidate’s half-hour-long advertisement last year did not change channels after the first few minutes.
　　以上内容对GMAT逻辑考试中的常见题型及解题技巧进行了详细的讲解，考生可以根据文中重点进行针对性的练习，掌握并熟练应用GMAT逻辑试题的解题思路，从而在GMAT考试中取得好成绩。