OG的题和GWD这题有区别吧。 OG题干里已经说明:what these farmers saved on insecticide rarely exceeded their extra costs for seed. 而GWD这道只是说modified过的种子杀虫剂用量少了,但是并没说明价格,tatal=quantity*price, so B can evaluate the argument! E选项,也只是强调了用量的问题。如果普通种子和modified seed用同种insecticide可以evaluate , 否则还是不行,从这里也说明了E不对。而B不存在这个flaw