问题补充:
Generally speaking, when according to the directions, the medicine has no side effect.
A. taken
B. taking
C. to take
D. to be taken
答案:
(答案→)A. taken
B. taking
C. to take
D. to be taken
解析:考查状语从句的省略:句意:“通常说来,当被按照说明书服用时,这个要没有副作用。”应为这句话的主语是drug,所以应该是“被服用”,所以是when +过去分词。省略了the medicine is,选A。