1.在.之上. eg:on the table,write on the paper,lie on me 2.对于,关于.(此时可以和upon互换) eg:research on physics 3.在哪一天 eg:on Sunday,on a rainny day 4.通过 eg:on TV,on words 5.开着的,上演了 eg:the TV is on,the power is on,the programme is on,on the air(直播) 6.准时,刚好 eg:on time 7.存在 eg:on line(在线)
