GMAT逻辑CR难点

2022-06-06 16:37:29

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  一、假设题

  假设题,又称assumption题目。属于GMAT逻辑中增强类的一种特殊形式。通常需要寻找一个必要条件,使得文章结论成立。与增强题不同的是增强题是提高可能性,而假设题目是使之成立。从这层意义上说,假设题算数加强题的一种变体,因为都是要让结论成立。

  ① 标志性词语:assumption、an addition premise、depend on。

  ② 解题思路:寻找与文中逻辑链最相关的条件,且能够使结论成立的选项;

  ③ 解题技巧:把选项取否定,如因此推翻结论(变成削弱选项),则该选项是答案。

  例题:

  The higher the level of certain vitamins and minerals in the bloodstream, the better a person's lung function, as measured by the amount of air the person can expel in one second. The lung function of smokers is significantly worse, on average, than that of nonsmokers. Clearly, therefore, one way for smokers to improve their lung function is for them to increase their intake of foods that are rich in these helpful vitamins and minerals.

  Which of the following is an assumption on which this argument depends?

  (A) Smokers are less likely than nonsmokers to have diets that are rich in vitamins and minerals.

  (A) The lung function of smokers whose diets are rich in those vitamins and minerals is generally better than that of nonsmokers with comparable diets.

  (A) People whose diets are deficient in those vitamins and minerals do not typically have other health problems in addition to diminished lung function.

  (A) Stopping smoking will not typically improve lung function more than any diet changes can.

  (A) Smoking does not introduce into the body chemicals that prevent the helpful vitamins and minerals from entering the bloodstream.

  解析:血管中特定的V&M水平越高,人的肺功能越好,肺功能可由人在一秒呼出的空气量确定。吸烟者的肺功能平均来说要比不吸烟者差很多。 因此,很明显吸烟者提高肺功能的一种方式就是增加富含这些有益V&M的食物摄入。

  逻辑链:V&M越高,肺越健康 → 抽烟的人需要吃带有V&M的食物。

  假设题 (要保证多吃V&M就有用)

  A 吸烟者比不吸烟者更少可能吃富含V&M的食物 (抽烟的人是不是一般不会吃这些东西和这些东西能不能起到作用没有任何关系,与逻辑链无关,错误)

  B 富含V&M的饮食的吸烟者的肺功能比对应的不吸烟者更好 (意思是V&M配合吸烟食用更佳?不符合逻辑链,错误)

  C 饮食缺乏V&M的人除了肺功能下降外一般不会有其他健康问题 (其他健康问题,且没提吸烟者,跳出逻辑链,错误)

  D 停止抽烟在改善肺功能方面一般不会比饮食改变更有效 (停止抽烟,跳出逻辑链,错误)

  E 抽烟不会引入进身体一些化学物质,这些化学物质会阻止有益V&M进入血管 (只有当吸烟不影响吸收这些微量元素的时候,更多地摄取这些微量元素才能够使更多的微量元素进入血液,从而改善肺功能,符合逻辑链,正确)

  二、评价题

  评价题,又称evaluation题目或评估题。通常需要选出能够影响文章结论是否成立的选项。选项通常为whether/if引导的一般疑问句的陈述语句或特殊疑问句的陈述语句。

  ① 标志性词语:evaluate、assess、determine。

  ② 解题思路:对选项的不同回答如对结论造成不同影响,则该选项是答案。

  ③ 解题技巧:

  1、模糊词、极端词都不选;但极端结论可以选模糊词;

  2、对其答Yes或No对文章产生相反效果。

  例题:

  A certain cultivated herb is one of a group of closely related plants that thrive in soil with high concentrations of metals that are toxic to most other plants. Agronomists studying the growth of this herb have discovered that it produces large amounts of histidine, an amino acid that, in test-tube solutions, renders these metals chemically inert. Hence, the herb’s high histidine production must be the key feature that allows it to grow in metal-rich soils.

  In evaluating the argument, it would be most important to determine which of the following?

  (A) Whether the herb can thrive in soil that does not have high concentrations of the toxic metals

  (B) Whether others of the closely related group of plants also produce histidine in large quantities

  (C) Whether the herb’s high level of histidine production is associated with an unusually low level of production of some other amino acid

  (D) Whether growing the herb in soil with high concentrations of the metals will, over time, reduce their concentrations in the soil

  (E) Whether the concentration of histidine in the growing herb declines as the plant approaches maturity

  解析:某一种草药是一组可以在有害的高金属含量的土地当中生存的植物当中的一种,农学家研究发现,这种草药的生长产生了大量的H,一种氨基酸。试管实验证明,H这种物质可以使这些金属产生惰性。因此,草药产生的H这种物质一定是它在这种金属含量高的土地生长的的解决办法关键因素。

  逻辑链:草药生成H氨基酸→草药可以在金属含量高的土壤中生长

  评价题(H氨基酸是不是保证生长的原因?)

  A.这种草药是不是可以在没有这么高浓度的有害金属的土壤里面生存 (无关选项)

  B 其他相关植物是否也可以产生大量的H这种物质 (正确,如果不可以,他们也可以在这种土壤中生存,说明能不能生存与H这种物质无关,反之,若也产生了,则与H这种物质有关)

  C H这种物质浓度的产量是否与其他某种氨基酸的产量异常低有关 (无关选项)

  D 生长在高浓度金属土壤中的草药是否会降低土壤中金属的浓度 (说明这种草药可能会吸收这种金属,或者分解,但与H没有关系。不能影响结论)

  E 是否随着植物接近成熟,土地中H的浓度降低 (无关选项)

  以上就是关于“GMAT逻辑CR难点”的内容,相信大家对接下来的备考内容,有更清晰的了解。考试成绩的高分,并不是一蹴而就的,大家还是需要踏踏实实的练习备考,才能真正的提升我们的分数。

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