一道题求助~

dontwanna

T-3-Q3.
Scientists have made genetic modifications to cotton to increase its resistance to insect pests. According to farmers’ report, the amount of insecticide needed per acre to control insect pests was only slightly lower for those who tried the modified seed than for those who did not. Therefore, since the modified seed costs more than ordinary seed without producing yields of higher market value, switching to the modified seed would be unlikely to benefit most cotton farmers economically.
Which of the following would it be most useful to know in order to evaluate the argument?

A.Whether farmers who tried the modified cotton seed had ever tried growing other crops from genetically modified seed.
B.Whether the insecticides typically used on ordinary cotton tend to be more expensive than insecticides typically used on other crops.
C.Whether for most farms who grow cotton it is their primary crop
D.Whether the farmers who have tried the modified seed planted as many acres of cotton, on average, as farmers using the ordinary seed did.
E.Whether most of the farmers who tried the modified seed did so because they had previously had to use exceptionally large quantities of insecticide.
答案B.为什么？
为什么不选e?

lavenderwu

文章中給了兩者使用殺蟲劑的數量關係，E還是數量關係，但B是價格關係。知道了數量和價格就可以得出那一個更經濟了。

nianbohu

evaluate的题目需要的选项是yes或no的答案会从不同方面（strength或weak）给予argument评价。
如果是B的话，回答no，是可以增强argument的，因为在售价都相同的情况下，ordinary crop总成本低，利润高，没必要switch。
但是回答yes的话，是不能确定一定是削弱argument的，因为ordinary crop的农药成本高，然而 modified crop的种子成本高，在没给出其他条件下，这两项没办法比较究竟是ordinary crop还是modified crop的总成本低，根本无法得出到底是哪一种的利润高，需不需要switch。对评价argument没有帮助。

所以还是E对。E的提出明显是在质疑原文例子的有效性。回答yes，则举例不当，例子中使用modified crop的农民的土地本身就需要使用大量农药，而现在农药使用量和其他正常土地使用量一样，不就表明modified crop是有效减少了农药的使用量，modified crop总成本减少，利润高，所以有必要switch，削弱了argument。回答no，则例子有效，增强argument。

nianbohu

本人上面一帖有个说错的地方，E中农药使用量和其他正常土地使用量一样，表明modified crop是有效减少了农药的使用量，可是因为modified crop种子价格高，是得不出modified crop总成本减少的结论的。
但是，其实对E回答yes，实质上是否定证明argument的例子的有效性，这就直接是削弱了argument啊，回答No, 增强了例子的有效性，增强了argument，这样根本就不用考虑究竟结论中是不是需要switch的问题了。

Jackjokes

69. Scientists have modifi ed feed corn genetically,
increasing its resistance to insect pests. Farmers who tried out
the genetically modifi ed corn last season applied less
insecticide to their corn fi elds 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 modifi ed seed would
be unlikely to increase profi ts.
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 yields, but against which commonly used
insecticides and the genetic modifi cation 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 modifi
ed corn last season applied more insecticide
than was actually necessary
(E) Whether, for most farmers who plant feed corn, it is their
most profi table crop
Argument Evaluation
Situation Farmers who grew feed corn genetically engineered to be
pest resistant got yields
comparable to those of farmers growing ordinary feed corn, but
did so while using less
pesticide. Since the amount saved on pesticide was rarely in
excess of the extra costs for
the genetically modifi ed corn, most farmers will probably not
increase profi ts by choosing
the genetically engineered variety.
Reasoning Which would be most useful to know in evaluating the
argument? To answer a question such
as this, one should look for information that would strengthen or
weaken the argument.
If one had information that the farmers growing the genetically
modifi ed corn could
have increased their yields last year at lower cost, this would
be helpful in evaluating the
argument, because this would show that the argument is weak.
A It does not matter to the argument whether there are pests
against which pesticides and genetic
resistance are equally ineff ective, because that is compatible
with there being pests against which
they are not equally eff ective.
B Whether prices of feed corn go up or down aff ects the
comparison groups equally.
C Th e relative cost of insecticides for other crops has no
bearing on the argument because the
argument is concerned with only feed corn.
D Correct. Th is option provides the information that it would be
most useful to know in evaluating
the argument. It shows that farmers growing genetically modifi ed
corn last year could have
attained higher profi ts than they in fact did.
E Th e argument concerns only the relative profi tability of
growing one variety of feed corn versus
another.
Th e correct answer is D.

puzzledog

我原本也选的E，后来觉得还是B对
Fact已经给出了，只用比较两种seed的成本，modified seed原始成本高，（农药使用量，产量相同，注意：only slightly lower就基本等同于相同）ordinary seed与modified seed后期成本谁高? 即谁使用的农药贵

Western

LZ确定答案吗？我同意2L我觉得是D，原文的结论是modified seed costs more than ordinary seed without producing yields of higher market value，也就是花费高，产量还小。

D选项说要看farmers是不是种modified seed 的数量，因为有可能因为这是新品种，所以农民们种的少，所以产量太低。
D选项取正加强，取非削弱，很明显是答案