下列行为中符合校园礼仪要求的是[       ]

A．奏唱国歌时要肃立、脱帽、行注目礼或队礼    

B．偷看他人信件和日记  

C．同学之间起外号    

D．校园内遇见老师，学生先行

—Do you know the differences ________ the three words?  --Sorry, I don’t know.

A．among

B．between

C．with

D．about