Q3:

Scientists have made genetic modifications to cotton to increase its resistance to insect pests. According to farmers’ reports, 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?

1. Whether farmers who tried the modified cotton seed had ever tried growing other crops from genetically modified seed
2. Whether the insecticides typically used on ordinary cotton tend to be more expensive than insecticides typically used on other crops
3. Whether for most farmers who grow cotton it is their primary crop
4. Whether the farmers who have tried the modified seed planted as many acres of cotton, on average, as farmers using the ordinary seed did
5. Whether most of the farmers who tried the modified seed did so because they had previously had to use exceptionally large quantities of insecticide

Answer

理不出思路，请高手指教。

我倾向于B.主要看insecticide 有没有问题.

大家感兴趣的就来讨论一下吧.

D更好，已试种过转基因作物的农民最清楚这种作物有没有经济价值，若有，多种，没有，少种（平均而言），因此他们种植的量可以作为评判标准。

欢迎批评指正

应该选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

平均/acre modified seed 和ordinary seed 一样多才具有比较性

modified seed 种植密度很高，ordinary seed 平均/acre 种植很少，nsecticide差不多则说明modified seed 好。