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?作者: lavenderwu 时间: 2013-4-1 06:44
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.作者: puzzledog 时间: 2013-4-7 07:34
