OG13的67和68，请求讲解！

哎呦喂喂

67.Several industries have recently switched at least partly from older technologies powered by fossil fuels to new technologies powered by electricity. It is thus evident that less fossil fuel is being used as aresult of the operations of these industries than would have been used if these industries had retained their older technologies.

Which of the following, if true, most strengthens the argument above?
A. Many of the industries that have switched at least partly to the new technologies have increased their output.
B. Less fossil fuel was used to manufacture the machinery employed in the new technologies than was originally used to manufacture the machinery employed in the older technologies.
C. More electricity is used by those industries that have switched at least partly to the new technologies than by those industries that have not switched.
D. Some of the industries that have switched at least partly to the new technologies still use primarily technologies that are powered by fossil fuels.
E. The amount of fossil fuel used to generate the lectricity needed to power the new technologies is less than the amount that would have been used to power the older technologies.

我说一下我的理解，这道题我觉得是因果关系，且A和D选项已经排除，可以说是和原题推理没有关系。我原来选的是B选项，而且感觉B和C实际说的差不多。但是答案好似E。求大神指点。


68. Scientists have modified feed corn genetically, increasing its resistance to inset pests. Farmers who tried out the genetically modified corn last season applied less insecticide to thier corn fields and still got yields comparable to those they would have gotten with ordinary corn. Ordinary corn seed, however, costs less, and what these farmers saved on insecticide rarely exceeded their extra costs for seed. Therefore, for most feed-corn farmers, switching to genetically modified seed would be unlikely to increase profits.

Which of the following would it be most useful to know in order to evaluate the argument?
A. Whether there are insect pests that sometimes reduce feed-corn fields, but against which commonly used insecticides and the genetic modification are equally ineffective.
B. Whether the price that farmers receive for feed corn has remained steady over the past few years.
C. Whether the insecticides typically used on feed corn tend to be more expensive than insecticides typically used on other crops.
D. Whether most of the farmers who tried the genetically modified corn last season applied more insecticide than was actually necessary.
E. Whether, for most farmers who plant feed corn, it is their most profitable crop.

这题答案是D。但是在原文中已经说到了“Farmers who tried out the genetically modified corn last season applied less insecticide to their corn fields..." 且我认为题中B和E选项没有关系。
求大神指点。

哎呦喂喂

tophoenix 发表于 2015-8-12 13:32
第一个，看结论，问是否省油。 所以看他的电是从多少油来的。

第二个，他是说，除草时只能在庄稼小的时候 ...

那么67的B选项提到了，less fossil fuel在the new technologies中被使用，不就说到了通过switch to new technologies来达到less fossil fuel了吗？

alzn2765

67.
前提（因）：Several industries have recently switched at least partly from older technologies powered by fossil fuels to new technologies powered by electricity
结论（果）：less fossil fuel is being used as aresult of the operations of these industries than would have been used if these industries had retained their older technologies.

前提和结论之间有一个gap。这个gap就是E选项。没有E选项，结论不能成立。这题本质是一个assumption题。
B选项只说了生产the machinery employed in the new technologies需要的fossil fuel少，可如果这个new technologies machine本身operation反而消耗更多的 fossil fuel 呢？结论显然不能成立了。

68.
给你举个例子：
种转基因玉米种子售价100元，因为转基因技术抗虫害只需要用很少的杀虫剂假设100元，则种转基因玉米的成本是200元。如果种非转基因种子售价10元，但是因为非转基因技术不抗虫害需要用很多的杀虫剂假设250元，则种非转基因玉米的成本是260元。现在的比较是种转基因玉米成本比较低，所以比较赚钱。
现在给一帮以前没种过转基因玉米的农民种转基因玉米，他们花100元买种子，因为不了解转基因玉米究竟需要喷多少杀虫剂，所以按照之前种非转基因玉米用杀虫剂的量来估计，减了点儿用了200元的杀虫剂。最后，这些种转基因玉米的农民的成本是300元。他们说种转基因玉米还要花300元，非转基因玉米才260元。不划算。

他们不赚钱的原因究竟是转基因玉米不好还是因为他们用了比转基因玉米需要的杀虫剂多的量？

你现在再看D，是不是明白了？

哎呦喂喂

alzn2765 发表于 2015-8-12 14:17
67.
前提（因）：Several industries have recently switched at least partly from older technologies po ...

那么请问68的A选项呢？

alzn2765

哎呦喂喂 发表于 2015-8-12 22:28
那么请问68的A选项呢？

这里有两个case:用转基因种子和用非转基因种子，如果有一种变量对两个case产生相同的影响（ equally ineffective），你觉得这个两个case产生不同的结果可能是这个变量导致的吗？

方程1如果比方程2大，方程1减去5可能比方程2减去5小吗？

ansionjoe

楼主，我其实能够理解你为什么会选错的原因。
题目的结论：It is thus evident that less fossil fuel is being used as aresult of the operations of these industries than would have been used if these industries had retained their older technologies.
1、看问题，说的是most strengthens the argument above?
然后B选项是看似对，他的意思：生产那些利用新科技的设备（用电的）所耗掉的化石燃料比生产老设备用掉的化石燃料要少！ 他能够加强论据，但是是不是最强的呢？要看准是，生产利用新科技的设备！！仅仅这个设备而已。
C完全是扯淡，本题跟用电多少无关。
E选项，说的是用来产生电所需要的化石燃料，要比直接用来生产所需要的化石燃料要少。
好，BE，我们做个对比，看下取非是不是能够削弱，B来说，生产设备用的化石燃料多了，但是如果生产电用的化石燃料少的话，依然不能削弱。
E如果转到新科技电能驱动的话，而生产电能所利用的化石燃料更多，那么对题目的结论是肯定削弱的！当然，如果生产这个机器所利用的化石燃料更多的话，那么也会有一定影响。
而且，题目主要直说的生产方式的转变，因此E更好。

ansionjoe

楼主，第二个题目，他的结论是，用基因改良种子，并不比用普通种子带来的收益高，原因，1、基因种子贵，用的农药少2、普通种子便宜，用农药多  所以才得出上面的结论。
问题是Which of the following would it be most useful to know in order to evaluate the argument? 其实这里主要证明他给的原因，推出结论是合理的，也就是原因不存在任何问题，而结论也不存在任何问题。
也就是，下面的选项如果成立，那么结论成立，如果不成立那么结论不成立。
A 一种害虫，无论是基因改良玉米，还是杀虫剂都对之无效，这个跟结论并没有关系啊
B 五年内玉米种子价格是否稳定，这个也是没啥关系，如果这么说，普通玉米种子价格是否稳定，那么可能就对了
C不对，题目已经说了杀虫剂节省了钱
D正确选项，如果没有用过量，那么他的结论是对的，如果用了过量，那么他的结论是错的！
E 无关选项

哎呦喂喂

ansionjoe 发表于 2015-8-13 05:37
楼主，第二个题目，他的结论是，用基因改良种子，并不比用普通种子带来的收益高，原因，1、基因种子贵，用 ...

非常感谢！

哎呦喂喂

alzn2765 发表于 2015-8-12 23:18
这里有两个case:用转基因种子和用非转基因种子，如果有一种变量对两个case产生相同的影响（ equally inef ...

非常感谢！我再回去思索一下