help~！！！prep 37 逻辑 key is D，我能选出来，但咋想不明白捏~！！！！

bob9603

37.(32356-!-item-!-188;#058&006101)

Capuchin monkeys in Venezuela often rub a certain type of millipede into their fur.Secretions of these millipedes have been shown to contain two chemicals that are potent mosquito repellents, and mosquitoes carry parasites that debilitate the capuchins.The rubbing behavior is rare except during the rainy season, when mosquito populations are at their peak.Therefore, the monkeys probably rub the millipedes into their fur because doing so helps protect them against mosquitoes.

Which of the following would it be most useful to determine in order to evaluate the argument?

(A) Whether the two chemicals provide any protection for the millipedes against their own predators

(B) Whether the type of millipede used by the capuchin monkeys in Venezuela is found in other parts of the world

(C) Whether animals other than capuchins rub insects of any kind into their fur

(D) Whether the only time the millipedes are readily available to the capuchins is during the rainy season

(E) Whether secretions of any other insects accessible to the capuchins contain chemicals that repel mosquitoes

kevingod

如果millipedes只在下雨天才有，这样也能解释题干中的“rare",那么此时结论不成立。如果millipedes在任何时候都有，那么题干中结论成立。这就是D选项想要表达的。

bob9603

如果millipedes只在下雨天才有，这样也能解释题干中的“rare",那么此时结论不成立。如果millipedes在任何时候都有，那么题干中结论成立。这就是D选项想要表达的。

-- by 会员 kevingod (2012/3/3 22:48:39)

亲，我好像还没有弄懂，您能否说个逻辑思路出来，我怎么总是这么混乱呢这题，谢谢啦先~！！！

kevingod

事件：
雨天——蚊子多——猴子用millipedes rub，非雨天——蚊子少——猴子rarely用millipedes rub

结论：猴子是否用millipedes rub与蚊子数量多少有关，数量多时要rub是为了驱蚊。
D选项：是否还与millipedes的限制有关，如果millipedes只在雨天才有，而其他天气没有，也可能导致的上述的事件发生（比如不为驱蚊，只是为了止痒，这种虫子止痒效果好，但是只在雨天才有，这也说得通啊），这样就与蚊子无关了，那么这就构成了对结论的削弱。

bob9603

事件：
雨天——蚊子多——猴子用millipedes rub，非雨天——蚊子少——猴子rarely用millipedes rub

结论：猴子是否用millipedes rub与蚊子数量多少有关，数量多时要rub是为了驱蚊。
D选项：是否还与millipedes的限制有关，如果millipedes只在雨天才有，而其他天气没有，也可能导致的上述的事件发生（比如不为驱蚊，只是为了止痒，这种虫子止痒效果好，但是只在雨天才有，这也说得通啊），这样就与蚊子无关了，那么这就构成了对结论的削弱。

-- by 会员 kevingod (2012/3/3 23:34:00)

我好想知道我卡在哪里了~D的意思：如果是only time 的时候 m有，那么就有rub m的行为，那么就可以驱蚊（支持观点）
                                                        可是，如果不是only time的时候 才有 m，换句话说，m好像什么时候都有，这其中就包括rainy season，那么，rub m的行为也有可能有，那么就可以驱蚊~（这个我就不知道了）


我好像卡在了这里，容我在想想啊kevin哥~

ainiAnnie

我们先来分析题目，
Capuchin monkeys in Venezuela often rub a certain type of millipede into their fur.Secretions of these millipedes have been shown to contain two chemicals that are potent mosquito repellents, and mosquitoes carry parasites that debilitate the capuchins.
在V地区的monkeys经常rub一种特定的昆虫M使其进入他们的fur，M分泌的物质包含了两种化学成分，是强有效的防蚊剂，and 蚊子是V地区monkeys 的天敌。（简化就是蚊子是Monkeys的天敌，Ms经常使用rub昆虫M，强烈暗示 Ms rub M的原因就是为了防蚊。此时更需警惕！！说不定你已经掉到它的逻辑陷阱了！！）
The rubbing behavior is rare except during the rainy season, when mosquito populations are at their peak.
此处的 rare非常重要，是逻辑漏洞。
这句话说 平时 Ms这种行为很少，然而在下雨天的时候比较频繁，此时刚好蚊子也在高峰期。
Therefore, the monkeys probably rub the millipedes into their fur because doing so helps protect them against mosquitoes.
从而顺利得出结论：Ms rub M 就是问了防蚊。
这里出现了一个逻辑错误：它加强论证的条件认为 同时发生的事情之间必然存在 因果关系。其实不是这样的。答案D提供了另外一种可能，Ms 在雨季 rub 频繁的原因是 只有在雨季才有昆虫M，从而不能顺利推出结论。也是我们评价这个结论最有用的信息。

bob9603

我们先来分析题目，
Capuchin monkeys in Venezuela often rub a certain type of millipede into their fur.Secretions of these millipedes have been shown to contain two chemicals that are potent mosquito repellents, and mosquitoes carry parasites that debilitate the capuchins.
在V地区的monkeys经常rub一种特定的昆虫M使其进入他们的fur，M分泌的物质包含了两种化学成分，是强有效的防蚊剂，and 蚊子是V地区monkeys 的天敌。（简化就是蚊子是Monkeys的天敌，Ms经常使用rub昆虫M，强烈暗示 Ms rub M的原因就是为了防蚊。此时更需警惕！！说不定你已经掉到它的逻辑陷阱了！！）
The rubbing behavior is rare except during the rainy season, when mosquito populations are at their peak.
此处的 rare非常重要，是逻辑漏洞。
这句话说 平时 Ms这种行为很少，然而在下雨天的时候比较频繁，此时刚好蚊子也在高峰期。
Therefore, the monkeys probably rub the millipedes into their fur because doing so helps protect them against mosquitoes.
从而顺利得出结论：Ms rub M 就是问了防蚊。
这里出现了一个逻辑错误：它加强论证的条件认为 同时发生的事情之间必然存在 因果关系。其实不是这样的。答案D提供了另外一种可能，Ms 在雨季 rub 频繁的原因是 只有在雨季才有昆虫M，从而不能顺利推出结论。也是我们评价这个结论最有用的信息。

-- by 会员 ainiAnnie (2012/3/4 0:00:50)

我总感觉是否是only time并不能说明猴子rub是为了对抗蚊子~
我觉得应该是m的有无，才能说明是不是对抗蚊子。有m，则rub m，对抗蚊子；没m，则没有rub这个行为，则对抗不了蚊子~

保险起见，我还是沾过来比较好~

ainiAnnie

这道题不是要分析有没有蚊子啊。。。。你思路想歪了。。。。

子弹青春

Elimination is better for this question.

D is not a good evaluation for this argument because no mater D is established or not we can not make sure that the conclusion in this argument is right or wrong. D just provided a guidance to let us find the assumption between the rubbing and the protection. On the other hand, no other options is useful. So D is the answer.

Elimination can help us to start from the end of the precess above saving our times.

bob9603

Elimination is better for this question.

D is not a good evaluation for this argument because no mater D is established or not we can not make sure that the conclusion in this argument is right or wrong. D just provided a guidance to let us find the assumption between the rubbing and the protection. On the other hand, no other options is useful. So D is the answer.

Elimination can help us to start from the end of the precess above saving our times.

-- by 会员 子弹青春 (2012/3/4 22:04:02)

thank you very much ~!! i get it ~