还是要回到原题: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. 是拿用新种子的和没用新种子的比较。结果是只少一点。 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 没用以前是用得非常之多。exceptionally实际上也隐含了一个比较。 如果所以没用以前比其他人多很多,用了以后比其他人少一点,实际上还是节省了。