A. less difficult to control than non-point pollution B. the minor pollution source C. more difficult to control than non-point pollution D. a problem that cannot be solved 参考答案:A 答案解析:细节题 问按照作者的观点,地下水污染的有关情况如何。第二段讲地下水污染的形成及国家所采取的降低和杜绝污染的措施。再加Unlike point sources,these source of wate