_____,follow the directions on the bottle carefully.A．When taken drugs B．When drugs e takenC.When one takes drugs D．When taking drugs
问题描述：
_____,follow the directions on the bottle carefully.
A．When taken drugs B．When drugs e taken
C.When one takes drugs D．When taking drugs
答
选 D
从主句里边的follow the directions可以判断这是个祈使句,其实就是省略了主语you,根据这个,从句和主句的主语必须保持一致,所以when状语从句的主语也应该是you,所以排除了B和C
A选项是过去分词,说明药被吃,主语不是you
D是正确答案,这里是分词短语做状语,其实还原成从句就变成When you are taking drugs ,省略了you are而已