加拿大研究生考試GRE閱讀經(jīng)典邏輯題分析

熟悉論證關系、熟練判斷論點論據(jù)是絕殺GRE閱讀不可或缺的手段。這需要系統(tǒng)的理論方法與大量的練習實踐共同作用。而下面這道題目在找到目標結論這一步上就難倒了眾多同學。

我們一起來看看這個貌似有很多結論的邏輯削弱題到底應該怎么去處理。GRE閱讀

Even after numerous products made with artificial sweeteners became available,sugar consumption per capita continued to rise.Now manufacturers are introducing fat-free versions of various foods that they claim have the taste and texture of the traditional high-fat versions.Even if the manufacturers'claim is true,given that the availability of sugar-free foods did not reduce sugar consumption,it is unlikely that the availability of these fat-free foods will reduce fat consumption.

Which of the following,if true,most seriously undermines the argument?

A.several kinds of fat substitute are available to manufacturers,each of which gives a noticeably different taste and texture to products that contain it.

B.the products made with artificial sweeteners did not taste like products made with sugar.

C.the foods brought out in sugar-free versions did not generally have reduced levels of fat,but many of the fat-free versions about to be introduced are low in sugar.

D.people who regularly consume products containing artificial sweeteners are more likely than others to consume fat-free foods.

E.not all foods containing fat can be produced in fat-free versions.

答案：B

解析：

B代糖吃起來并不像糖，因為口味有差異，所以糖原本的消耗沒有減少。所以當代脂吃起來像高脂肪的時候，可能就降低了脂肪的消耗。能成功代替。

其他選項

A.代脂問世，且嘗起來不一樣。反向選項，加強了結論。嘗起來不一樣，才會有人繼續(xù)買真脂肪。

C.低糖不一定低脂，但是低脂一定低糖。有區(qū)別，但是跟糖耗和脂耗都不相關。無關選項。

D.人工糖的消費者比無脂肪的消費者多。人工糖的消費者多，不代表糖的消費者比高脂的消費者多。雖然有比較，但沒有達到目標，無關選項。學在加拿大

E.并不是所有含脂肪的食物都可以改造成無脂的模式。

從題干可清晰知道此題為邏輯削弱題，需要針對文章結論進行削弱。然而，難住很多的同學第一個問題就是，這么多看起來像結論的地方，到底削弱誰？終極目標結論到底在哪里？

GRE閱讀沒有并列主要結論，出現(xiàn)多個結論時一定有主次之分，此時必然是針對主要結論進行削弱。

加拿大研究生考試GRE閱讀經(jīng)典邏輯題分析

今天為大家提供判定主要結論的方式之一：將來時態(tài)是主要結論。順帶說一句，只看位置前后去判斷主次結論風險極大。慎用！

因此，本文主要結論是：...it is unlikely that the availability of these fat-free foods will reduce fat consumption.

直接推翻結論，削弱之后目標結論為：...it is unlikely that the availability of these fat-free foods will not reduce fat consumption.

此時出現(xiàn)第二個問題，對于類比的理解是否準確。類比論證是GRE閱讀中經(jīng)?？疾榈囊环N論證方式，其意義往往并非只停留在表面，需要我們深層挖掘。通過文章將可替代脂肪與代糖類比可知：代糖的出現(xiàn)不能讓糖的消耗降低，所以可替代脂肪的出現(xiàn)也不能導致脂肪消耗降低。