求教！！两道归纳题取非的比较

哈哈傻笑君

题目1，来自PREP12：

Increases in the level of high-density lipoprotein (HDL) in the human bloodstream lower bloodstream cholesterol levels by increasing the body's capacity to rid itself of excess cholesterol. Levels of HDL in the bloodstream of some individuals are significantly increased by a program of regular exercise and weight reduction.

Which of the following can be correctly inferred from the statements above?

• A
  
  Individuals who are underweight do not run any risk of developing high levels of cholesterol in the bloodstream.
  
  
  
• B
  
  Individuals who do not exercise regularly have a high risk of developing high levels of cholesterol in the bloodstream late in life.
  
  
  
• C
  
  Exercise and weight reduction are the most effective methods of lowering bloodstream cholesterol levels in humans.
  
  
  
• D
  
  A program of regular exercise and weight reduction lowers cholesterol levels in the bloodstream of some individuals.
  
  
  
• E
  
  Only regular exercise is necessary to decrease cholesterol levels in the bloodstream of individuals of average
  
  
  

答案是D

题目2 OG 16-53

Humans get Lyme disease from infected ticks. Ticks get infected by feeding on animals with Lyme disease, but the ease of transmission from host animal to tick varies. With most species of host animal, transmission of Lyme disease to ticks is extremely rare, but white-footed mice are an exception, readily passing Lyme disease to ticks. And white-footed mouse populations greatly expand, becoming the main food source for ticks, in areas where biodiversity is in decline.

The information in the passage most strongly supports which of the following?

• A
  
  In areas where many humans are infected with Lyme disease, the proportion of ticks infected with Lyme disease is especially high.
  
  
  
• B
  
  Very few animals that live in areas where there are no white-footed mice are infected with Lyme disease.
  
  
  
• C
  
  Humans are less at risk of contracting Lyme disease in areas where biodiversity is high.
  
  
  
• D
  
  Ticks feed on white-footed mice only when other host species are not available to them.
  
  
  
• E
  
  The greater the biodiversity of an area, the more likely any given host animal in that area is to pass Lyme disease to ticks.
  
  
  

答案是C




两道题目对比一下，第一题的B选项我理解的错误的原因是因为双边取非却未取反，因此与原文不符，，，，，然而第二道题目的正确选项C只双边取非但没取反，为什么就是对的呢，，，是因为其他的选项和C选项相比更不好吗？？？
还是我理解错啦？？？还请各位大神盆友们帮忙解答一下，，，谢谢啦啦啦拉拉！！！

momojiayou

Increases in the level of high-density lipoprotein (HDL) in the human bloodstream lower bloodstream cholesterol levels by increasing the body's capacity to rid itself of excess cholesterol. Levels of HDL in the bloodstream of some individuals are significantly increased by a program of regular exercise and weight reduction.
这道题的逻辑思路是 increases in the level of HDL 可以 lower choleseterol level,怎么降低呢？方法是通过增强身体内自我消除多余cholesterol的机能。第二句表明重点是，在一个programme 里，通过regular exercise and weight reduction,一些人的HDL level increased. 这两句话本身没有直接的因果联系。
Which of the following can be correctly inferred from the statements above?
A
Individuals who are underweight do not run any risk of developing high levels of cholesterol in the bloodstream.
B
Individuals who do not exercise regularly have a high risk of developing high levels of cholesterol in the bloodstream late in life.--这个选项不正确是因为它把第二句一个项目的结果当成了因果联系。因为这个项目里面一些人通过运动和减肥可以增加cho level，并不能说明不运动和减肥就有高风险。这个中间有很多gap,其他没有增加level的人是什么原因，题中并没有指出，所以不足推论。
C
Exercise and weight reduction are the most effective methods of lowering bloodstream cholesterol levels in humans.
D
A program of regular exercise and weight reduction lowers cholesterol levels in the bloodstream of some individuals.--这个选项正确，是因为它直接分析了题中第二句的意思，用另外一个方式表达，没有绝对，也没有多余的猜测。
E
Only regular exercise is necessary to decrease cholesterol levels in the bloodstream of individuals of average
希望能有帮助，也谢谢分享，欢迎其他解释。

alex_heyday

by a program of regular exercise and weight reduction感觉很关键
这里是同时满足俩个条件才可行，
所以D是相当于直接了当表达了此意
B它只表明了LACK OF EXERCISE的人，这里感觉与题无关，in other words，逻辑结构有点问题，a&b导致C（降低胆固醇），但其余逻辑链可能都有点问题，（我不太懂这种非A则BALBLABLA这种逻辑）








答案是D

Ajorz

B选项的late in life是最明显的错误吧

hihiha

apple345526817 发表于 2016-6-4 16:58
第一题你的解释是正确的，这是我没有考虑到的。但是我不觉得逆否命题是CR中的考点，我们限时做题的时候很 ...

同意！               

apple345526817

哈哈傻笑君 发表于 2016-6-2 15:32
这两道题我又思考了一下，或许问题不在于取非取反的问题，第一题题干中说的是some individuals，而B选项没 ...

第一题你的解释是正确的，这是我没有考虑到的。但是我不觉得逆否命题是CR中的考点，我们限时做题的时候很难这么想的，对于第一题，我觉得我们应该反思为何没有看到正确选项，而匆忙选择了B选项。
PS我还是认为是一个绝对值与相对值的概念，就是你说的可能性，A的上升导致B的上升，绝对不能说A很低，所以B很低，只能说A很低会使得B相对很低，相对低就是你说的一种可能性，个人角度不太建议从逆否角度出发思考问题。

apple345526817

哈哈傻笑君 发表于 2016-6-2 15:32
这两道题我又思考了一下，或许问题不在于取非取反的问题，第一题题干中说的是some individuals，而B选项没 ...

同意！               

哈哈傻笑君

apple345526817 发表于 2016-6-2 14:10
我感觉第一题与第二题还是不太一样，因为第一题的B选项表述为"不运动就会导致很高的胆固醇”，表述混淆了绝 ...

这两道题我又思考了一下，或许问题不在于取非取反的问题，第一题题干中说的是some individuals，而B选项没说some,扩大了范围，错误的点不在于后面的双项取非，而是主语。尽管双项取非未取反和原因意思是不一致的（逆否命题才可以和原命题一致），但逆命题发生的可能性较高，B选项的后半部分意思并不是"不运动就会导致很高的胆固醇”，而是“不运动就会有高风险导致很高的胆固醇”，其实还是一种高可能性，所以后半部分没错，错在主语。

而第二道题目双向取非了未取反，也不是逆否命题，只是否命题，同上面一样，并不一定是百分百发生，而是有较高的可能性，因此选项中说了 are less at risk of，所以是正确的。

不知道理解的对不对，欢迎继续讨论～～～

apple345526817

我感觉第一题与第二题还是不太一样，因为第一题的B选项表述为"不运动就会导致很高的胆固醇”，表述混淆了绝对概念与相对概念，根据原文只能说不运动的人含有相对更高的胆固醇，我们只知道运动能减少胆固醇。因此选项D就很好的符合argument中的逻辑链，运动--》降低胆固醇。

而第二题正确选项C，虽然是取非，但是他的表示是相对概念，其表述为“high biodiversity--》less infected people”，根据原文high biodiversity--》less infected ticks--》less infected people，所以C选项是正确的，但是假如表述为high biodiversity --》 little infected people我觉得就不对了，因为这样就犯了混淆相对概念与绝对概念，因为可能含有它因导致little infected people，less ticks只能说less infected people，绝对不能说little infected people。

不知道自己的解释是否合理，因为自己也遇到这两个题，所以自己总结了一下~欢迎一起讨论

不知道

哈哈傻笑君

自顶自顶