请教PREP新版破解CR2的两道逻辑题 95 100 谢谢

fay009

95. (28538-!-item-!-188;#058&002980)
Which of the following most logically completes the passage?
Using new detection techniques, researchers have found trace amounts of various medicinal substances in lakes and rivers.  Taken in large quantities, these substances could have serious health effects, but they are present in quantities far too low to cause any physiological response in people who drink the water or bathe in it.  Nevertheless, medical experts contend that eliminating these trace amounts from the water will have public health benefits, since __________.
A. some of the medicinal substances found in lakes and rivers are harmless to humans even if taken in large quantities
B. some of the medicinal substances found in lakes and rivers can counteract possible harmful effects of other such substances found there
C. people who develop undesirable side effects when being treated with medicines that contain these substances generally have their treatment changed
D. most medicinal substances that reach lakes or rivers rapidly break down into harmless substances
E. disease-causing bacteria exposed to low concentrations of certain medicinal substances can become resistant to them

答案是E。我想选择B。我觉得E和题目没有什么关系啊。
题目是说 研究者发现一些医用物质在河里。如果大量吸收，这些物质会引发健康疾病，但是他们现在量都很低，不会引起引用它们的人们的生理反应。然而，医学专家认为应该消除这些东西是很有益的，因为——
B，一些物质会和一些物质反应产生有害的影响
E。致病细菌在低浓度的这些物质中间会对它们有抵抗力
不知道是我题目意思理解错了么？

100. (30745-!-item-!-188;#058&005748) (T-9-Q28. ???-7-13 , different type)
Lyme disease is caused by a bacterium transmitted to humans by deer ticks.  Generally, deer ticks pick up the bacterium while in the larval stage by feeding on infected white-footed mice.  However, certain other species on which the larvae feed do not harbor the bacterium.  If the population of these other species were increased, more of the larvae would be feeding on uninfected hosts, so the number of ticks acquiring the bacterium would likely decline.
Which of the following would it be most important to ascertain in evaluating the argument?
A. Whether populations of the other species on which deer tick larvae feed are found only in areas also inhabited by white-footed mice
B. Whether the size of the deer tick population is currently limited by the availability of animals for the tick's larval stage to feed on
C. Whether the infected deer tick population could be controlled by increasing the number of animals that prey on white-footed mice
D. Whether deer ticks that were not infected as larvae can become infected as adults by feeding on deer on which infected deer ticks have fed
E. Whether the other species on which deer tick larvae feed harbor any other bacteria that ticks transmit to humans

答案怎么会选择B呢。
我的理解：
文章意思，风湿病是由于一种通过deer ticks传给人类的细菌引起的。一般来说，deer ticks带上这种病菌当它们还是幼虫的时候，通过吃infected white-footed mice. 然而，幼虫吃的一些其他的种类没有这个细菌。如果其他种类的老鼠增加了，更多的幼虫就会寄宿在没有感染的宿主上，所以感染这个细菌的ticks就会减少。
下面哪个应该要evaluate。
A。是否tick能寄宿的其他种类只有在white-footed mice也在的地方才能找到
B。时候tick的数量现在被限制了，因为tick幼虫可以寄宿的动物（不available）
C。明显不对。。
D。是否ticks在幼年时候没有被感染可以在成年时候被感染，当寄宿在infected deer曾经寄宿过的deer身上
E。无关选项。。
我怎么觉得应该是选择A呢。。

弥小岛

100题都不怎么能看懂...

tyd727

taq45ceci 发表于 2012-8-29 13:56
所以這題解題的關鍵在於 tick 的數量：假設原始有 30 隻幼虱，uninfected host: infected host = 1:1均勻分 ...

好例子~~~~~

醒醒Shine

辛小白 发表于 2013-6-7 18:56
95的B应该是some出错了吧 一些能中和 那不中和的那些substance就是不好的啊 虽然量小但是还是有害的 所以如 ...

支持你的观点。
GMAT做多了会发现，对于这种只有some、a number of的现象，是没有办法attack原命题的。在GMAC看来都是部分，不能一篇概全。

辛小白

95的B应该是some出错了吧 一些能中和 那不中和的那些substance就是不好的啊 虽然量小但是还是有害的 所以如果去掉的话还是对健康有帮助的

Audre

guyuan0126 发表于 2010-5-17 10:51
95.一开始我也选了B,后来发现漏了原本结论的关键词"eliminating"。。。B 是削弱了experts的claim. ...

同看漏eliminating..

jate

counteract:vt. 抵消；中和；阻碍;      95，B选项说明的是这个M物质能中和有害物质，说明不消除M物质反而更好！！所以明显的E是对的

alicezyk

所以這題解題的關鍵在於 tick 的數量：

假設原始有 30 隻幼虱，uninfected host: infected host = 1:1
均勻分布在這些 hosts 身上，則 uninfected 幼虱 = 15 隻，infected 幼虱 = 15 隻。
今天若增加 uninfected host 的數量至 uninfected host: infected host = 2:1

[情境一]：
如果 tick 的數量不會因為宿主的種類變多而增加，
則這 30 隻幼虱也是均勻分布在宿主上，則 uninfected 幼虱 = 20 隻，infected 幼虱 = 10 隻。
在這個情況下，infected 幼虱數量從 15 隻變成 10 隻 → argument 的結論成立。
(結論： the number of ticks acquiring the bacterium would likely decline)


[情境二]：
如果 tick 的數量會因為宿主的種類變多而增加，假設增加到 60 隻，
調整後染菌及非染菌宿主比例依然是 uninfected host: infected host = 2:1
並且這 60 隻幼虱也均勻分布在宿主上，
則 uninfected 幼虱 = 40 隻，infected 幼虱 = 20 隻。
在這個情況下，infected 幼虱數量從 15 隻變成 20 隻 → argument 的結論不成立。

-- by 会员 taq45ceci (2012/8/29 13:56:26)

好解释啊！！！考试遇到这种题 我这个水平的就直接PASS掉了。

taq45ceci

所以這題解題的關鍵在於 tick 的數量：

假設原始有 30 隻幼虱，uninfected host: infected host = 1:1
均勻分布在這些 hosts 身上，則 uninfected 幼虱 = 15 隻，infected 幼虱 = 15 隻。
今天若增加 uninfected host 的數量至 uninfected host: infected host = 2:1

[情境一]：
如果 tick 的數量不會因為宿主的種類變多而增加，
則這 30 隻幼虱也是均勻分布在宿主上，則 uninfected 幼虱 = 20 隻，infected 幼虱 = 10 隻。
在這個情況下，infected 幼虱數量從 15 隻變成 10 隻 → argument 的結論成立。
(結論： the number of ticks acquiring the bacterium would likely decline)


[情境二]：
如果 tick 的數量會因為宿主的種類變多而增加，假設增加到 60 隻，
調整後染菌及非染菌宿主比例依然是 uninfected host: infected host = 2:1
並且這 60 隻幼虱也均勻分布在宿主上，
則 uninfected 幼虱 = 40 隻，infected 幼虱 = 20 隻。
在這個情況下，infected 幼虱數量從 15 隻變成 20 隻 → argument 的結論不成立。

bonniii

2楼对第一题的解释也有点问题，原文没说medicinal substance是不好的，字面解释medicinal应该是褒义的，文章只说量太大会有影响。E选项的佐证也应该说明medicinal是能杀病毒的