OG 逻辑两题求助 （diagnostic 26， 34）

heidiym

1. Guillemots are birds of Arctic Regions. They feed on fish that gather beneath thin sheets of floating ice, and they nest on nearby land. Guillemots need 80 consecutive snow-free days in a year to raise their chicks, so until average temperatures in the Arctic began to rise recently, the guillemots' range was limited to the southernmost Arctic coast. Therefore, if the warming continues, the guillemots' range will probably be enlarged by being extended northward along the coast.

Which of the following, if true, most seriously weakens the argument?
A. Even when the warming trend continues, there will still be years in which guillemot chicks are killed by an unusually early snow.
B. If the Arctic warming continues, guillemots' current predators are likely to succeed in extending their own range farther north.
C. Guillemots nest in coastal areas, where temperatures are generally high than inland areas.
D. If the Arctic warming continues, much of the thin ice in the southern Arctic will disappear.
E. The fist that guillemots eat are currently preyed on by a wilder variety of predators in the southernmost Arctic regions than they are farther north.

Ans: D

我在纠结B。因为我觉得因为predator到背面了，所以即使天气暖和，Guillemots 也没有办法向北扩展，所以就weaken了呀。

2. 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.

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.
(8) 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.

Ans:E.

我在纠结C， 别的都可以排除掉。因为选E的话的确说明了因为广告所以sale上涨，但是profit依然是负的呀，所以还是没有economic interests的吧。C的话广告钱少sale少。如果E是正确的，应该考虑sale， 那么C也考虑sale 而不是profit的话，C没有理由是错的呀。

求大神帮忙啦~~

zsf1993428

C选项说的是便宜的campaign, 和结论的campaign不是一回事

zsf1993428

26题我觉得D和B都能weaken,但是D更能weaken, 毕竟在前提里出现了D选项的thin ice。个人看法，求大牛解释

heidiym

zsf1993428 发表于 2014-5-11 21:08
C选项说的是便宜的campaign, 和结论的campaign不是一回事

我的逻辑是 因为说了generally campaign越贵越有效果，所以weaken了最后的结论就是campaign是对economic interests有作用的。。求解释！

zsf1993428

zsf1993428 发表于 2014-5-11 21:10
26题我觉得D和B都能weaken,但是D更能weaken, 毕竟在前提里出现了D选项的thin ice。个人看法，求大牛解释 ...

Answer choice C is a perfect example of hand waving. A cheaper campaign would have brought in less new customers. This sounds like a tempting answer choice, but again the issue of quantifiable numbers would help tremendously. If the campaign cost 90% less but brought in 50% less customers, would it have been a success? Or if the alternative had cost 50% less but brought in 90% fewer customers? Both situations are possible from the statement, but they have different outcomes. Answer choice C can be true without weakening the conclusion in any way, so it cannot be the correct choice, although many people are tempted by this answer.

zsf1993428

zsf1993428 发表于 2014-5-12 12:57
Answer choice C is a perfect example of hand waving. A cheaper campaign would have brought in less ...

https://www.veritasprep.com/blog/2013/09/find-the-correct-answer-in-critical-reasoning-on-the-gmat/
google出来的，我觉得这个解释不错   

heidiym

zsf1993428 发表于 2014-5-12 12:57
Answer choice C is a perfect example of hand waving. A cheaper campaign would have brought in less ...

好的谢谢 这么解释是解释的通啊 但是吧。。我觉得想的这么多哎 感觉一般题目都不会想的这么深入的样子。。

sherrygong1101

虽然是过了很久了，不知道楼主是否考完了，不过也为了给其他刚刚开始复习GMAT的伙伴们看看这两题的我的解题思路吧
很凑巧，这两题是我做的时候唯一错的两题，而我选的答案和你认为的答案一样，不过后来我发现自己错得太幼稚了。
第一题：结论是guillemots' range will probably be enlarged by being extended northward along the coase.注意being extended northward，这三个单词告诉我们这个鸟居住范围的扩大是通过往北方延伸，因此要削弱这个结论就是要找一个条件能证明一下两个可能性：1)气候上升了，鸟居住范围不会变大；2)鸟的居住范围不是仅仅通过向北方延伸来扩大的
这样子解释后是否发现选项D就是削弱结论的了呢？因为很多thin ice在southern arctic将会消失，因此鸟的食物本来会聚集在冰下面的，现在不会了，因此鸟的食物没有了，因此他们就会离开南方向北方走，但是离开了南方，面积变小了，向北方走，面积在增大，这两个面积的负效应和正效应我们不得而知，因此选项D削弱了结论；
选项B:我相信楼主一开始和我犯了一个同样的错误，就把predator的意思给搞错了，以为predator是吃鸟的，对吗？如果predator是吃鸟的话，那么选项B的表达就不会像题干里写的那样(guillemots' current predators)，而是应该写成 predators which prey on guillemots or only predators;

第二题：还是看结论：clearly, therefore, the campaign did nothing to further Dietz's economic interests，要削弱结论，就是要找一个条件或者一个claim能证明这个广告campaign indeed did something to further D economic interests，考虑可能性会是大环境都不好，因此虽然profit不够，但销量上去了也能证明这个campaign是有用的；
选项C:一个更便宜的广告campaign本应该可以比D去年用的campaign带来更少的新客户，好，这里引入第三者来仅仅说明了D现在用的广告campaign是BETTER THAN A LESS EXPENSIVE ONE的，至于这个campaign是否did something to further D economic interests， 这个选项没有提到过，因此不能削弱结论
选项E:in EACH of the past five years,每年都有全范围的吞拿鱼罐头销售的最低潮，意思就是说大环境不好，因此campaign能让D销售量上去已经是did something to further its economic interests了

好了，解释的有点复杂，其实归根结底就是一句话：CR做题一定要紧贴结论走，选项里面的话，不要自己延伸出去想，选项里面说道了A，那么就只有A，没有B也没有C,D,E。结论是做CR的关键，因此结论一定要找对，搭配premise，那么就可以更加有效地选出正确的答案了。

heidiym

sherrygong1101 发表于 2014-12-9 17:08
虽然是过了很久了，不知道楼主是否考完了，不过也为了给其他刚刚开始复习GMAT的伙伴们看看这两题的我的解题 ...

我已经考完了 不过真的谢谢你的回复 很详尽！祝你考试申请成功！

sherrygong1101

heidiym 发表于 2014-12-10 00:56
我已经考完了 不过真的谢谢你的回复 很详尽！祝你考试申请成功！

你考完了还回来看CD啊，哈哈！我后天一站，希望一切尽如人意！