A：1个
B：2个
C：3个
D：4个
——More and more students wear glasses in our school these days.——I agree with you. Students ___ keep on doing eye exercises to protect their eyes.
下列关于物质跨膜运输的叙述，错误的是 （ ）
①用水鉴别苯、乙醇、溴苯
和
溶液