If without following the doctor’s instructions, the medicine may have serious side effects.
A. taken
B. to be taken
C. taking
D. being taken
网友回答
A. taken
B. to be taken
C. taking
D. being taken
解析：考查状语从句的省略式：句意：如果不安医生的指导吃这个药，这个药可能有严重的副作用。当主从句的主语一致的时候，可以省略从句的主语和be动词，if taken=if the medicine is taken。选A。