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.
答案选B，不明白耶~~~请NN们指点下吧....
如果以前有讨论过了麻烦给我一个连接吧~~~ | 
