这题我觉得GWD答案错了 大家看看啦

pennyrun

28: GWD-29-Q9
Manatees, aquatic mammals inhabiting Florida
’s rivers and coastal waters, swim close to the surface andare frequently killed in collisions with boats. To address the problem, boat traffic in manatee-populated waters isbeing requiredto maintain very low speeds. Unfortunately, manatees are unable to hear low-pitched sounds and aboat’s sound lowers in pitch as the boat slows. Therefore, this approach may in fact make things worse rather thanbetter.Which of thefollowing, if true, casts most doubt onthe conclusion?
B  Because the water hyacinth that manateesfeed on grows best in water that is nearly still, water hyacinth beds can bedisturbed or damaged by fast-moving boat traffic.
E  When experimentersexposed manatees to the recorded sounds of boats moving at various speeds, thecreatures were unable to discern the sounds over normal background noise.
GWD给的答案是E，看了几个讨论帖 ，我还是觉得该选B。
海牛被船撞死很多。交通管制限制船速。
但是船开得慢则噪音小，海牛听不到，更容易被撞伤。
结论：这个方法带来坏处而不是好处。这才是要否定的结论

B:海牛的食物适于在静水中生长，船开得快会破坏其生长环境。
那么现在船开的慢了，使海牛食物多了，是有好处的，削弱结论。

E:给海牛放各种速度船的录音，它们根本不能将船的声音与背景噪音中区分开来。即船速快慢，噪音大小对海牛都一样。
这只是在说能听见的声音，与不能听见的声音根本无关，所以对结论无作用！

chasingM7

I go for E.

conclusion: this approach may in fact make things worse rather than better
Premises: 1) Manatees got killed if swimming close to surface
               2) to resolve this, low down speed
               3) Manatees cannot hear low-pitched voice

weaken? you wanna find an answer that proves the approach doesnt not worsen the problem.

B: 海牛的食物适于在静水中生长，船开得快会破坏其生长环境. ==> it is "still water". lower speed doesnt mean the water will be still. the end result might be the same because, after all, water is not still.

E: 给海牛放各种速度船的录音，它们根本不能将船的声音与背景噪音中区分开来。即船速快慢，噪音大小对海牛都一样 ==> this proves the approach doesnt contribute, either positively or negatively, to the problem. therefore, weaken the conclusion...

hope it helps.

pennyrun

谢谢解答！！不干我还是有疑问：B中我翻译得不到位，说的是nearly still，并不是完全静止。
而E，说的是区分不出背景噪音和各种音量的声音，还是觉得这个声音只局限于可以听见的那部分，对原题没有影响；而且，如果不是这样的话，这个条件和原题的条件就相悖了 好奇怪的选项

pennyrun

木有人呀木有人~~

清飞扬

I go for E.

conclusion: this approach may in fact make things worse rather than better
Premises: 1) Manatees got killed if swimming close to surface
               2) to resolve this, low down speed
               3) Manatees cannot hear low-pitched voice

weaken? you wanna find an answer that proves the approach doesnt not worsen the problem.

B: 海牛的食物适于在静水中生长，船开得快会破坏其生长环境. ==> it is "still water". lower speed doesnt mean the water will be still. the end result might be the same because, after all, water is not still.

E: 给海牛放各种速度船的录音，它们根本不能将船的声音与背景噪音中区分开来。即船速快慢，噪音大小对海牛都一样 ==> this proves the approach doesnt contribute, either positively or negatively, to the problem. therefore, weaken the conclusion...

hope it helps.

-- by 会员 chasingM7 (2011/8/18 17:43:13)

你厉害还分析B，我是直接把B给排掉了。根据你的reasoning process;其实这个stimulus就是关于：保护Manatees，而保护的方法就是开的慢
原文的结论是，因为Manatees听不见low pitch的声音所以否决了这个plan，而weaken的话，可以从devalidate这个原因入手，OG100后的几道题目都是这么思考的，让这个生成结论的原因失效。

E就是说了，不管是high pitch, low pitch都听不见，所以“原因无效”，因此这个结论不成立

B，根本就是和这个声音/保护计划没有关系，可以说是out of scope了

这个世界要做某个事情的方法有很多种，可是都得在premise的范围内才行，超出premise范围的方法就是错的

pennyrun

谢谢！麻烦可不可以给几道OG上面这种套路的题啊？我也来研究研究~~嘿嘿

凭什么上不了700

清飞扬 发表于 2011-8-18 22:14
I go for E.conclusion: this approach may in fact make things worse rather than betterPremises: 1) ...

同意！               

GMAT冲冲冲冲冲

我也选B
但是我觉得可以从结论上思考
this approach may in fact make things worse rather than better---weaken这个结论就是 this approach does not make things worse    所以关注的重点在于降低船速不会让things更糟 而不是会不会让事情更好
那文章要解决的问题是 be killed in collisions with boats，因此翻译过来文章讨论的就是：降低船速不会使更多的XX be killed in collisions with boats---从这个角度思考B是完全无关的