题目

 Organic food is produced from crops _____ chemicals, pests and so on. In one word, it is free from pollution of any kind.    A. that is free from      B. free of    C. free with     D. which are free of 答案：D张明将自家饮水机插入插座时，他家的熔断器中的熔丝立即熔断，下列原因分析不正确的是（　　）A．电路的总功率过大B．饮水机中的电热丝断了C．熔丝的额定电流太小D．饮水机短路