gwd-6-4 答案质疑,逻辑区的NN们请看过来

pebbles

Q4:

In the past the country of Siduria has relied heavily on imported oil.  Siduria recently implemented a program to convert heating systems from oil to natural gas.  Siduria already produces more natural gas each year than it burns, and oil production in Sidurian oil fields is increasing at a steady pace.  If these trends in fuel production and usage continue, therefore, Sidurian reliance on foreign sources for fuel should decline soon.

Which of the following is an assumption on which the argument depends?

1. In Siduria the rate of fuel consumption is rising no more quickly than the rate of fuel production.
   

   
   

2. Domestic production of natural gas is rising faster than is domestic production of oil in Siduria.
   

   
   

3. No fuel other than natural gas is expected to be used as a replacement for oil in Siduria.
   

   
   

4. Buildings cannot be heated by solar energy rather than by oil or natural gas.
   

   
   

5. All new homes that are being built will have natural-gas-burning heating systems.

答案是A.

我的问题:

"Siduria already produces more natural gas each year than it burns, and oil production in Sidurian oil fields is increasing at a steady pace.  If these trends in fuel production and usage continue",

如果天然气总是生产的比使用的多,那不就是说已经把A排除了吗?

我选了C,尽管有些勉强.

理由:题中结论是"Sidurian reliance on foreign sources for fuel should decline soon",但这个fuel 不一定等同于Gas或Oil. 感觉上像个逻辑上常见的考点:概念变化.

假如C成立,那可能该国还计划用别的燃料代替石油,如果这种燃料也可能是进口来的,就不能得出结论了.

感觉GMAT逻辑思路总是不那么清晰.答案有时不是那么有说服力.如果这题没有"If these trends in fuel production and usage continue"这句话,我绝对会选A.

请NN指点一下.多谢!

天之角

文中说S国现在要进口石油，其石油生产量每年稳步上升，以后就可以慢慢减少对进口的依赖了。但如果你否定了A，In Siduria the rate of fuel consumption is rising  more quickly than the rate of fuel production.不但不能减少进口，还要增加进口，无法得出作者的结论。

本文的结论是these trends in fuel production and usage continue, therefore, Sidurian reliance on foreign sources for fuel should decline soon. 个人感觉与gas的关系不大。

[此贴子已经被作者于2005-9-9 23:47:11编辑过]

pebbles

谢谢!

A的否定作用我是理解的.我的问题是"Siduria already produces more natural gas each year than it burns, and oil production in Sidurian oil fields is increasing at a steady pace.  If these trends in fuel production and usage continue",

文中说用气去替换油.如果如第一黑体所说,气产出总比使用多(应该包括替换油的部分),第二黑体说这样的产出和使用比率延续,那不管使用上升再多,气都够用啊.

其实我估计A就是出题者的答案,只是觉得上面的这些文字给这个答案的逻辑增添了不必要的混淆,使答案的说服力减弱,所以想听听NN的意见.

天之角

这样，如果按照你说的选C，没有别的替代燃料除了gas,gas每年开发超过可替代相当于100吨fuel，而A没有被考虑，如果每年石油的缺口为1000吨，还是不能减轻对进口的依赖啊。

pebbles

假设现在石油产量X,需求Y.进口缺口Y-X.

天然气因为"already produces more natural gas each year than it burns", 可以假设剩余正数Z.

如果将天然气补到石油上,缺口将为Y-X-Z.当然比Y-X小,所以可以说decline.注意结论并没有说不进口,只说进口减少而已.

而 "If these trends in fuel production and usage continue", 那么不管需求怎么增长,只要需求和国内产出的关系仍像上面一样,缺口还是会decline呀.我不明白作者为什么要来这么一句"If these trends in fuel production and usage continue" (至少一定程度上和A是相背的),否则A是很清楚的答案.

请问你觉得"If these trends in fuel production and usage continue"和A有一些矛盾吗?

[此贴子已经被作者于2005-9-10 2:01:33编辑过]

天之角

我觉得不矛盾，必须要有A的假设，these trends in fuel production and usage continue才能有它的意义，否则就向我上面说的，如果石油缺口每年都在增加，而天然气的节余每年都在减少，这个也符合文中所讲的趋势，但无法得到减轻进口依赖的结论。

pebbles

谢了!尽管我还是不能理解,仁者见仁,智者见智,呵呵.但愿考试不碰上这题,要不然我要扔硬币了

vivian_dong

这题我真的好晕啊，题里面不是已经讲了，gas的生产比消费高，oil的生产也在增加。Siduria already produces more natural gas each year than it burns, and oil production in Sidurian oil fields is increasing at a steady pace。 那A又说fuel（oil+gas)的生产比消费高。这不是题里面已经说明的吗？A还能算假设？难道是说，题里提的是gas消费小于生产，没说明oil是否消费小于生产，所以A才对？晕了，不知道说明白了没有。。请NN帮助！！

vivian_dong

自己顶。。真心求教！

vivian_dong

再顶！