一、用作介词,表示在...上;向,朝等含义。
The book is on the table.
书在桌子上。
The spider is walking on the ceiling.
蜘蛛在天花板上爬行。
They made their own judgment on his report.
他们凭他的报告作出自己的判断。
二、用作副词,表示向前(移动),进行着等含义。
Put your coat on.
穿上你的大衣.
Move on!
向前走!
She worked quietly all night.
她整个晚上默默地继续工作。
三、用作形容词,表示在进行的,在发生的等含义。
The televisionw set was on.
电视机开着。
The light were all full on.
灯火通明。