GMAT逻辑错误选项小结

一、 诉诸权威/大众信念/人身攻击/感情色彩等选项（非学者态度）
二、 反对前提的选项
三、 涉及两比较对象的选项
1． 比较双方应与题目比较双方一致（1。2。两点偶的观点和原文相反～～是我理解错了还是原文打错了啊？～～）
2． 比较的概念要与原文完全等同（涉及与原文无关的新概念的比较必错）
OG2. The average life expectancy for the United States population as a whole is 73.9 years, but children born in Hawaii will live an average of 77 years, and those born in Louisiana, 71.7 years. If a newlywed couple from Louisiana were to begin their family in Hawaii, therefore, [ their children would be expected to live longer than would be the case if the family remained in Louisiana. ]
Which of the following, if true, would most seriously weaken the conclusion drawn in the passage?
A. Insurance company statisticians do not believe that moving to Hawaii will significantly lengthen the average Louisiana’s life. (一、诉诸权威)
B. The governor of Louisiana has falsely alleged that statistics for his state are inaccurate. （二、反对前提）
C. The longevity ascribed to Hawaii’s current population is attributable mostly to genetically determined factors.
D. Thirty percent of all Louisiana’s can expect to live longer than 77 years. （三1、比较双方应与题目的一致。应为Hawaii VS. Louisiana，而非30%Louisiana VS the other 70%）
E. Most of the Hawaiian Islands have levels of air pollution well below the national average for the United States. （三2、比较概念应与题目的一致。应为 Life expectancy，而非 Pollution level）
3． 原并列内容变成比较，必错
OG33. Rural households have more purchasing power than do urban or suburban households at the same income level, [since some of the income urban and suburban households use for food and shelter can be used by rural households for other needs.]
Which of the following inferences is best supported by the statement made above?
A. The average rural household includes more people than does the average urban or
suburban household.
B. Rural households have lower food and housing costs than do either urban or suburban
households.
C. Suburban households generally have more purchasing power than do either rural or urban households.
D. The median income of urban and suburban households is generally higher than that of
rural households.
E. All three types of households spend more of their income on food and housing than on all other purchases combined.
四、 可能对，也可能不对的选项
五、 非提问要求的选项
5. A program instituted in a particular state allows parents to prepay their children’s future
college tuition at current rates. The program then pays the tuition annually for the child at any of the state’s public colleges in which the child enrolls. [Parents should participate in the program as a means of decreasing the cost for their children’s college education.]
Which of the following, if true, is the most appropriate reason for parents NOT to participate in the program?
A. the parents are unsure about which public college in the state the child will attend.   (四、有可能未来学费更高，也有更低的可能)
B. The amount of money accumulated by putting the prepayment funds in an interest-bearing account today will be greater than the total cost of tuition for any of the public colleges when the child enrolls.
C. The annual cost of tuition at the state’s public colleges is expected to increase at a faster rate than the annual increase in the cost of living. （五、题目问削弱，选项是加强）
D. Some of the state’s public colleges are contemplating large increases in tuition next year.（五、题目问削弱，选项是加强）
E. The prepayment plan would not cover the cost of room and board at any of the state’s public colleges.
六、 原文选项不在同一范畴 ((Out of Scope)
OG44. Some people have questioned the judge’s objectivity in cases of sex discrimination against women. But the record shows that in sixty percent of such cases, the judge has decided in favor of the women. [This record demonstrates that the judge has not discriminated against women in cases of sex discrimination against women.]
The argument above is flawed in that it ignores the possibility that
A. a large number of the judge’s cases arose out of allegations of sex discrimination against women
B. many judges find it difficult to be objective in cases of sex discrimination against women
C. the judge is biased against women defendants or plaintiffs in cases that do not involve sex discrimination 
D. the majority of the cases of sex discrimination against women that have reached the judge’s court have been appealed from a lower court
E. the evidence shows that the women should have won in more than sixty percent of the judge’s cases involving sex discrimination against women
（后面的这些原文没写例子，偶一下子也找不出，但都不难理解，等找到了再往上面补充吧～～）
七、 百分比和实际数量
八、 部分和整体
九、 相关性和因果性
十、 代表性问题 （Survey等的样本）
十一、 必要性和充分性（Necessity & Causaion）
十二、 含if, unless, as long as 等连词的选项，在归纳题中可能正确（是选项的前提必然成立）；在演绎题中必错（给出无关前提）