Follow the directions on the bottle carefully when .A. you will take the medicineB. takin

问题补充：

Follow the directions on the bottle carefully when .

A. you will take the medicine

B. taking the medicine

C. to take the medicine

D. taken the medicine

答案：

A. you will take the medicine

(答案→)B. taking the medicine

C. to take the medicine

D. taken the medicine

解析：前面是祈使句，后面的taking 这个动作由省略了的主语发出来。