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许多GMAT考生向笔者反映，目前的GMAT语法有日渐变难的趋势，尤其是对于同学们谈虎色变的GMAT语法中的逻辑类考题，大家经常很难看出题目当中所蕴涵的逻辑错误，从而导致莫名其妙的失分。针对这种现象，笔者对此类考题加以分析，希望对大家会有所帮助。
其实这种逻辑类考题并不像大家所想象的那样毫无规律，只要将历年真题加以总结就可以发现，这些题目还是可以有迹可循的。从总的方向来看，可以分为以下几个种类：
1． 事物的本身不能说明问题，事物的变化方能说明问题
这类考题和GMAT逻辑中的一类考题是非常类似的，仅仅通过事物的本身不能说明问题，事物变化的趋势和结果才能说明问题。比如我们看下面两道题目：
1.As the price of gasoline rises, which makes substituting alcohol distilled from cereal grain attractive, the prices of bread and livestock feed are sure to increase.
(A) which makes substituting alcohol distilled from cereal grain attractive
(B) which makes substituting the distillation of alcohol from cereal grain attractive
(C) which makes distilling alcohol from cereal grain an attractive substitute
(D) making an attractive substitution of alcohol distilled from cereal grain（E）
(E) making alcohol distilled from cereal grain an attractive substitute
这道题目中划线部分的which只能用来指代价格，但是价格的本身是不能说明用从谷物中蒸馏出来的酒精来做替代品变得更有吸引力的，油价上涨了这件事情方能说明，所以不能使用which，因为which只能指代一个特定的主体，它不能用来指代整个句子。应该用现在分词做伴随状语来表结果，所以答案应该选E，使用make n1 n2的句型。
2.Some of the tenth-century stave churches of Norway are still standing, demonstrating that with sound design and maintenance, wooden buildings can last indefinitely.
(A) standing, demonstrating that with sound design and maintenance, wooden buildings can last indefinitely
(B) standing, demonstrating how wooden buildings, when they have sound design and maintenance, can last indefinitely
(C) standing; they demonstrate if a wooden building has sound design and maintenance it can last indefinitely
(D) standing, and they demonstrate wooden buildings can last indefinitely when there is sound design and maintenance（A）
(E) standing, and they demonstrate how a wooden building can last indefinitely when it has sound design and maintenance
这道题目的意思是一些十世纪的教堂在挪威依然屹立着，展示了有着很好的设计和保养，木质结构可以无限延续下去，所以答案选A，同样用现在分词做伴随状语来表结果，而C，D，E的逻辑就错了，它们使用了they，只能指代复数名词教堂，变成教堂本身展示了有着很好的设计和保养，木质结构可以无限延续下去，这个逻辑是不对的，教堂本身怎么可能展示呢？比方说十世纪有个教堂，到了十一世纪就倒塌了，它所展示的意义不是刚好和原文相反了吗？所以教堂本身是不能展示的，教堂在挪威依然立着这件事情方能展示有着很好的设计和保养，木质结构可以无限延续下去。C，D，E的逻辑错误就明显属于事物的本身不能说明问题，事物的变化方能说明问题。
2． 词与词之间的逻辑搭配关系
这种题一般就属于难题了，它要求大家在考试的时侯要时刻保持清醒的头脑，注意正确的词与词之间的搭配关系。我们同样举几个例子：
3．As a baby emerges from the darkness of the womb with a rudimentary sense of vision, it would be rated about 20/500, or legally blind if it were an adult with such vision.
(A) As a baby emerges from the darkness of the womb with a rudimentary sense of vision, it would be rated about 20/500, or legally blind if it were an adult with such vision.
(B) A baby emerges from the darkness of the womb with a rudimentary sense of vision that would be rated about 20/500, or legally blind as an adult.
(C) As a baby emerges from the darkness of the womb, its rudimentary sense of vision would be rated about 20/500; qualifying it to be legally blind if an adult.
(D) A baby emerges from the darkness of the womb with a rudimentary sense of vision that would be rated about 20/500; an adult with such vision would be deemed legally blind.（D）
(E) As a baby emerges from the darkness of the womb, its rudimentary sense of vision, which would deemed legally blind for an adult, would be rated about 20/500.
这道题目正确的逻辑表述是当一个婴儿出现于子宫的黑暗当中，婴儿有着最初等的视觉，这个视觉将会被评为20/500，而一个成年人有着这样的视力将会被认为合法的瞎。首先A选项是不对的，它里面有两个代词it，第一个很明显指代视力，而第二个则是指代婴儿，这就违背了在同一句话中相同的代词应该指代相同事物的原则，所以A不对。这里?代视力，是视力将会被评为20/500，这没有问题，但是很遗憾这个定语从句后面还引导了legally blind as an adult，它的逻辑主语也是that,这样就变成视力合法的瞎了，这个逻辑就是有问题的，我们只能说人瞎，视力是无法说它瞎的。同样我们只能说人聋，听力是无法说它聋的，因此B选项就属于词与词之间的逻辑搭配关系错误。答案应该选D选项，后半分句是一个成年人有着这样的视力将会被认为合法的瞎，消除了逻辑搭配不当和代词指代的错误。
4.The physical structure of the human eye enables it to sense light of wavelengths up to 0.0005 millimeters; infrared radiation, however, is invisible because its wavelength—0.1 millimeters—is too long to be registered by the eye.
(A) infrared radiation, however, is invisible because its wavelength—0.1 millimeters—is too long to be registered by the eye
(B) however, the wavelength of infrared radiation—0.1 millimeters—is too long to be registered by the eye making it invisible
(C) infrared radiation, however, is invisible because its wavelength—0.1 millimeters—is too long for the eye to register it
(D) however, because the wavelength of infrared radiation is 0.1 millimeters, it is too long for the eye to register and thus invisible（A）
(E) however, infrared radiation has a wavelength of 0.1 millimeters that is too long for the eye to register, thus making it invisible
这道题目与刚才那道题的解题思路是完全一样的，我们再来体会一下这种题的出题特点。题干说人类眼睛的物理结构使它能感受到波长0.0005的光，然而射线是看不见的，因为它的波长是0.1，这太长了以至于不能够被眼睛探测到。A选项说波长看不见，这是个正确的逻辑，没有问题，然而B选项说射线的波长太长了以至于波长不能被看见，这就不对了。我们可以说射线看得见或是看不见，但是不能说波长看不见，因此B选项也属于词与词之间的逻辑搭配关系错误。
5．Although the term “psychopath” is popularly applied to an especially brutal criminal, in psychology it is someone who is apparently incapable of feeling compassion or the pangs of conscience.
(A) it is someone who is
(B) it is a person
(C) they are people who are
(D) it refers to someone who is（D）
(E) it is in reference to people
题干说尽管术语psychopath指的是一个特别残忍的罪犯，在心理学中它指的是某个人，他对别人没有同情心也不会受到良心的谴责。这道题的出题思路与上两道题略有不同，A，B选项谓语动词用了be动词，变成术语是某个人了，这个逻辑就错误了，术语指的是人而本身不是人，所以逻辑搭配错误，答案应该选D。
6．Promotions, retirements, deaths, and other actions approved by the board of directors at its May meeting will be reported in the July 15 issue of the company paper.
(A) Promotions, retirements, deaths, and other actions approved by the board of directors at its May meeting will be reported in the July 15 issue of the company paper.
(B) Promotions, retirements, and other actions which have been approved at the May meeting of the board of directors along with deaths, with be reported in the July 15 issue of the company paper.
(C) To be reported in the July 15 issue of the company paper are the promotions, retirements, deaths, and other actions which were approved at the board of directors’ May meeting.
(D) Meeting in May, the promotions, retirements, and other actions approved by the board of directors, including obituaries, will be reported in the July 15 issue of the company paper.（E）
(E) The July 15 issue of the company paper will report on promotions, retirements, and other actions approved by the board of directors at its May meeting; the paper will also include obituaries.
这道题目的难度比较大，考场中如果不能保持清醒的头脑，很有可能会把题目做错。题干的意思是提升，退休，死亡，和其他活动在五月份的董事会议上被批准了，这将会在7月15日的公司报章上有所报道。稍加分析我们就会发现问题，提升和退休可以被批准，死亡怎么能被批准呢，这明显属于词与词之间的逻辑关系搭配错误。答案应该选E，句子的最后另起了一个分句，这个文章也会包括死亡报告，消除了逻辑错误，而且用了obituaries是death的书面语，更符合商业英文的习惯。
3．事物本身不能和它自身进行比较，要把自身排除在外
这类考题又是考察了另外一种解题思路，事物在与其他事物进行比较时一定要把自身排除在外，因为自身和自身进行比较是没有任何意义的。一般情况下这种题目的正确答案都会加上other这个词。
7．Los Angeles has a higher number of family dwellings per capita than any large city.
(A) a higher number of family dwellings per capita than any large city
(B) higher numbers of family dwellings per capita than any other large city
(C) a higher number of family dwellings per capita than does any other large city
(D) higher numbers of family dwellings per capita than do other large cities（C）
(E) a high per capita number of family dwellings, more than does any other large city
题干说落杉矶有更高的人均家庭住宅要比任何一个大城市，很明显落杉矶本身也是个大城市，它不能和自身进行比较，所以A错，答案选C，加了other以后就把落杉矶自己排除在外了。
8．It is not likely that the competitive imbalance that now exists between Japan with all major industrial nations will be redressed during the foreseeable future.
(A) with all major industrial nations will be redressed during
(B) with all other major industrial nations will be redressed within
(C) with all other major industrial nations will be redressed during
(D) and all major industrial nations will be redressed during（E）
(E) and all other major industrial nations will be redressed within
此题考点与上题完全一样。题目的意思是不可能有竞争性的平衡存在于日本和所有的工业国家之间，日本本身也是个工业国家，要把自身排除在外，答案选E，加了other。
4．逻辑主语和谓语动词的搭配问题
这类考题是逻辑类考题中最多的，但所幸这类题目并不难，对此类题目熟悉后一眼就能找出题目中所蕴涵的错误。细分起来它又可以分为如下三类：
a.分词的省略结构要求其逻辑主语必须和主句主语一致
9．Upset by the recent downturn in production numbers during the first half of the year, the possibility of adding worker incentives was raised by the board of directors at its quarterly meeting.
(A) the possibility of adding worker incentives was raised by the board of directors at its quarterly meeting
(B) the addition of worker incentives was raised as a possibility by the board of directors at its quarterly meeting
(C) added worker incentives was raised by the board of directors at its quarterly meeting as a possibility
(D) the board of directors raised at its quarterly meeting the possibility of worker incentives being added（E）
(E) the board of directors, at its quarterly meeting, raised the possibility of adding worker incentives
这道题目属于典型的分词省略结构类型的考题，题干放了过去分词upset, 意思是被最近的销售上的下降所沮丧了，谁被沮丧呢，逻辑主语必然是人，所以A，B，C的逻辑都是错误的，因为它们的主语不是人，答案应该选E，把句子的主语换为了管理者的董事会，应该是他们被沮丧了。
10. In assessing the problems faced by rural migrant workers, the question of whether they are better off materially than the urban working poor is irrelevant.
(A) In assessing the problems faced by rural migrant workers, the question of whether they are better off materially than the urban working poor is irrelevant.
(B) The question of whether the rural migrant worker is better off materially than the urban working poor is irrelevant in assessing the problems that they face.
(C) A question that is irrelevant in assessing the problems that rural migrant workers face is whether they are better off materially than the urban working poor.
(D) In an assessment of the problems faced by rural migrant workers, the question of whether they are better off materially than the urban working poor is irrelevant.（D）
(E) The question of whether the rural migrant worker is better off materially than the urban working poor is irrelevant in an assessment of the problems that they face.
题干的逻辑是在评估农村里迁徙工人所面临的问题时，他们在物质上是否比城市里面工作的穷人更好的这个问题与之是不相关的。这个逻辑明显是不对的，谁来评估这个问题，逻辑主语明显应该是人，A的主语是question明显是不对的。再稍加分析我们就可以发现，原文中并没有出现人，也就是说这个评估的对象是不存在的，所以无法使用分词的省略结构，这时的正确答案是D选项，它把assessing改为了assessment，即分词结构名词化了，名词是可以没有逻辑主语的，这就避免了逻辑主语错误的问题。大家可以好好体会这种解题的思路。
b.形容词的省略结构
这类题其实与分词的省略结构考题大同小异，只不过将分词改为了形容词。
11. Once common throughout the Western plains, black-footed ferrets are thought to have declined in number as a result of the poisoning of prairie dogs, their prey.
(A) black-footed ferrets are thought to have declined in number as
(B) it is thought that the decline in number of black-footed ferrets is
(C) the decline in the number of black-footed ferrets is thought of as
(D) that black-footed ferrets have declined in their numbers is thought to be（A）
(E) the numbers of the black-footed ferret are thought to have declined as
题目的意思是曾经在西部的平原上很普遍，黑色脚的雪貂被认为在数量上减少了作为毒害草原上狗的结果。句首用了形容词的省略结构，主语应该放置普遍的对象，A选项的主语是雪貂，可以作为普遍的逻辑发出者，而B，C，D，E都属于逻辑主语的搭配错误，所以答案选A。
c.逻辑主语未出现时主动要改为被动
相比之下这类考题就稍有难度了，大家应该知道在我们GMAT语法当中有主动优于被动的原则，也就是说在均可使用的情况下，主动要优于被动，因为主动相对来说比较简洁，但如果句子的逻辑主语并没有出现，此时就无法使用主动了，这种情况下就一定要把主动改为被动。比如我们看下面一道例题：
12．Alaska regularly deposits some of its profits from the sale of oil into a special fund, with the intention to sustain the state’s economy after the exhaustion of its oil reserves.
(A) fund, with the intention to sustain the state’s economy after the exhaustion of its oil reserves
(B) fund, the intention of which is to sustain the state’s economy after they have exhausted their oil reserves
(C) fund intended to sustain the state’s economy after oil reserves are exhausted
(D) fund intended to sustain the state’s economy after exhausting its oil reserves（C）
(E) fund that they intend to sustain the state’s economy after oil reserves are exhausted
题目的意思是阿拉斯加规则的存了一些利润从油的销售到一个特别的基金里面去，为了来维持这个州的经济在它的石油储备被销售完了之后。B选项用了they作为消耗石油储备的动作发出者，这个逻辑是不对的，因为前面复数名词只有利润profits，那么they就只能指代利润，而利润不可能发出消耗石油储备这个动作。同样E选项也用了they指代利润，利润不可能倾向于维持州的经济，所以逻辑也错。D选项用了分词的省略结构，但由于我们细看原文，并没有出现消耗石油储备这个动作的逻辑主语，所以无法使用分词的省略结构。答案应该选C，用了被动虽然相对来说不如主动简洁，但是由于句子的逻辑主语没有出现所以只能使用被动。
5． 转折关系中事物的分类标准必须统一
这类考题考得不多，但正因为这样大家可能也会对它感到比较陌生。比如下面这道题目：
13.Although dozens of New York’s small museums are either devoted to local history or various ethnic groups, there are many one-of-a-kind museums from Manhattan to the Bronx that are open for exploration on summer weekends.
(A) Although dozens of New York’s small museums are either devoted to local history or various ethnic groups, there are
(B) Although dozens of New York’s small museums are devoted to local history or various ethnic groups,
(C) Dozens of New York’s small museums are devoted to local history or various ethnic groups, but there are
(D) Dozens of New York’s small museums are devoted to local history or various ethnic groups, and there are also
(E) Devoted to local history or various ethnic groups, dozens of New York’s small museums and also
题干的意思是尽管很多纽约的小博物馆被致力于发展当地历史或不同的道德团体，还存在有很多单一性的博物馆，它们开放为了夏季周末的研究学习。我们可以发现although是表示转折关系，但这个分类标准是不统一的。前面的分类标准是大和小，而后面的则是单一性还是多样性，完全有可能有这么一种博物馆，它既属于小博物馆又是一种单一性的博物馆，这样就产生逻辑上的前后矛盾了。所以这里不能使用转折关系，答案应该选D，使用并列关系就不存在这种问题了。
上面对GMAT语法中最常见的逻辑类考题进行了归类，相信会对广大考生有所帮助。最后大家一定要注意，GMAT语法的最高境界也就是语言的最高境界就是句子意思清楚无误的表达，在此程度上才能追求语法的正确和语言的优美。运用之道，存乎一心。原则是灵活的并非一成不变，但逻辑的正确性是永远要追求的。希望大家在解题时要时刻注意选项是否已经将句子的逻辑意思正确表达出来，这才是正确选项所一定要具备的特征。
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