要了解这种图解构建法我们首先要从理解逻辑题中最简单的逻辑关系开始，分析和总结出一套可预测的正确答案完备组，使得考生在考前训练时能从各个角度进行思维训练。
一、GMAT逻辑中的因果关系简介。
1、定义：因果关系是逻辑考试的核心逻辑关系之一(另一逻辑是转折逻辑)，也是进行解题的基础。通常文章内容较为繁杂，在有限的时间内需要我们具备迅速找到核心逻辑的能力。所以因果关系的迅速识别至关重要。
2、因果关系词：Therefore/Thus/Consequently/Since/Clearly/For this reason/For/In order to/Because/So/As a result/Conclude/Thanks to…
二、几种不同的因果关系举例。
1、GMAT逻辑题中的简单的因果关系。
1)并列关系表因果。
例如：Electrodes would be inserted into the soil, and the current between them would kill bugs and weeds and make crop plants stronger.
原因：Electrodes would be inserted into the soil, and the current between them would kill bugs and weeds。
结论：Make crop plants stronger。
2)主宾关系表因果。
例如：An overly centralized economy, not the changes in the climate, is responsible for the poor agricultural production in Country X since its new government came to power.
原因：An overly centralized economy。
结论：The poor agricultural production in Country X。
2、GMAT逻辑题中的复杂的因果关系
1)原因的原因
例如：Since furniture must be useful, cabinetmakers must exercise their craft with an eye to the practical utility of their product. For this reason, cabinetmaking is not art.
原因的原因：Since furniture must be useful,
原因：Cabinetmakers must exercise their craft with an eye to the practical utility of their product.
结论：Cabinetmaking is not art.
2)结论中的原因
例如：As per capita income in Gortland has risen toward the world average, per capita consumption of meat has also risen toward the world average, and it takes several pounds of grain to produce one pound of meat. Therefore, since per capita income continues to rise, whereas domestic grain production will not increase, Gortland will soon have to import either grain or meat or both.
原因：As per capita income in Gortland has risen toward the world average, per capita consumption of meat has also risen toward the world average, and it takes several pounds of grain to produce one pound of meat.
结论中的原因：Since per capita income continues to rise, whereas domestic grain production will not increase,
结论：Gortland will soon have to import either grain or meat or both.
3)并列双因
例如：No major agricultural crop matures from seed in as little as forty-five days. Synthetic herbicides, on the other hand, although not any longer-lasting, can be reapplied as the crop grows. Clearly, therefore, for major agricultural crops, plowing rye into the soil can play no part in effective weed control.
原因1：No major agricultural crop matures from seed in as little as forty-five days.
原因2：Synthetic herbicides, on the other hand, although not any longer-lasting, can be reapplied as the crop grows.
结论：For major agricultural crops, plowing rye into the soil can play no part in effective weed control.
4)类比逻辑
例如：Homeowners aged 40 to 50 are more likely to purchase ice cream and are more likely to purchase it in larger amounts than are members of any other demographic group. The popular belief that teenagers eat more ice cream than adults must, therefore, be false.
前提：Homeowners aged 40 to 50 are more likely to purchase ice cream
结论：Teenagers eat more ice cream than adults must, therefore, be false.
(详情请看 GMAT逻辑因果关系详解)
三、GMAT逻辑图构建步骤
1、前提与结论的因果要素。
Homeowners aged 40 to 50 are more likely to purchase ice cream and are more likely to purchase it in larger amounts than are members of any other demographic group. The popular belief that teenagers eat more ice cream than adults must, therefore, be false.
前提：Homeowners aged 40 to 50——>purchase ice cream
结论：Teenagers——>not eat more ice cream than adults
2、调整相同要素。
not teenager= Homeowners aged 40 to 50
前提：Homeowners aged 40 to 50——>purchase ice cream
结论：Homeowners aged 40 to 50——>eat more ice cream
3、找出概念差异。
not teenager= Homeowners aged 40 to 50
加强： purchase ice cream = eat more ice cream
削弱： purchase ice cream ≠ eat more ice cream
4、答案的完备组
1)前提：有效性
前提有效：增强前提与结论之间的必然联系
前提无效：削弱前提与结论之间的必然联系
2)结论：必然性
加强结论：排除使结论不成立的他因
削弱结论：引入使结论不成立的他因
3)关系：唯一性
架桥：前提与结论概念之间等价
断桥：前提与结论概念之间不等价
唯一性：排除使结论成立的他因
非唯一性：引入使结论成立的他因
(详情请看 GMAT逻辑链解题法)
四、GMAT逻辑图构建步骤例题演示
例一：Weaken
A year ago, Dietz Foods launched a yearlong advertising campaign for its canned tuna. Last year Dietz sold 12 million cans of tuna compared to the 10 million sold during the previous year, an increase directly attributable to new customers brought in by the campaign. Profits from the additional sales, however, were substantially less than the cost of the advertising campaign. Clearly, therefore, the campaign did nothing to further Dietz's economic interests.
前提： the advertising campaign——>reduce profits
结论： the advertising campaign——>no economic interests
削弱： reduce profits ≠ no economic interests
Which of the following, if true, most seriously weakens the argument?
(A) Sales of canned tuna account for a relatively small percentage of Dietz Foods' profits.
(B) Most of the people who bought Dietz's canned tuna for the first time as a result of the campaign were already loyal customers of other Dietz products.
(C) A less expensive advertising campaign would have brought in significantly fewer new customers for Dietz's canned tuna than did the campaign Dietz Foods launched last year.
(D) Dietz made money on sales of canned tuna last year.
(E) In each of the past five years, there was a steep, industry-wide decline in sales of canned tuna.
例二：Support
Excavation of the ancient city of Kourion on the island of Cyprus revealed a pattern of debris and collapsed buildings typical of towns devastated by earthquakes. Archaeologists have hypothesized that the destruction was due to a major earthquake known to have occurred near the island in A.D. 365.
前提： earthquakes——>devastated towns
结论： earthquake in A.D. 365——>devastated towns
加强： earthquakes = earthquake in A.D. 365
Which of the following, if true, most strongly supports the archaeologists' hypothesis?
(A) Bronze ceremonial drinking vessels that are often found in graves dating from years preceding and following A.D. 365 were also found in several graves near Kourion.
(B) No coins minted after A.D. 365 were found in Kourion, but coins minted before that year were found in abundance.
(C) Most modern histories of Cyprus mention that an earthquake occurred near the island in A.D. 365.
(D) Several small statues carved in styles current in Cyprus in the century between A.D. 300 and A.D. 400 were found in Kourion.
(E) Stone inscriptions in a form of the Greek alphabet that was definitely used in Cyprus after A.D. 365 were found in Kourion.
(详情请看 GMAT逻辑因果推理解题法)
GMAT逻辑图解构建法今天为大家用两道例题进行了分析，这种方法也可以看作是逻辑链解题法的一个种类。如果您觉得好用可以学习一下。
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