A. chemical poisons are only used when necessary B. chemical poisons are used very often C. pests are completely destroyed D. farmers do not have to worry about pests 参考答案:A 答案解析:文章第二段第四句中提到,在IPM 中只有必要时才使用有毒的化学药品,所以[D]有毒的化学药品经常被使用不符合题意,第二段第五句中又指出“农害物联合治理计划承认这样的事实,即试图用化学毒药完全消灭农害物