题目

根据“绿色化学”的要求，下列做法不合理的是（ ） A . 改进造纸厂生产工艺，减少废水排放 B . 农业生产时用化肥代替农家肥料，提高作物产量 C . 优化能源结构，开发新能源以减轻对化石燃料的依赖 D . 对金属产品回收利用，减少矿石开采 答案：B--I don’t know       .-- You can go and ask Jack.A．when does the train leaveB．that we will plant trees or notC．if she had come yesterdayD．what I should buy for him