【正确答案】 A

【答案解析】解析：细节题。根据文中的“Colombia is the source of most of the cocaine and heroin used in the U．S．Drugs”和“Before Colombia became our leading supplier”，可知答案选A。

【正确答案】 A

【答案解析】解析：细节题。文中列举了两个解决措施，“spraying plant-killing chemicals on acres of drug plantations”与“paying farmers to grow other crops”，前者为在毒品种植园中喷药，后者为给农民付钱种植其他农作物。所以答案是A。

【正确答案】 D

【答案解析】解析：推断题。最后一段，“Colombian farmers say coca brings in the most money and they are unsure the Colom-bian government will keeps its promise to help make other crops just as profitable．”哥伦比亚的农民认为种植co-ca可以带来可观的收入，他们不能保证政府会履行“种植其他农作物也能同样有利润”的承诺。所以选D。