no是电器开还是关的意思

on与off例句：

Sam was flicking a flashlight on and off

萨姆啪啪不停地把手电筒开了又关。

She was the ideal American teenager, both on and off screen.

无论是在荧幕上还是在生活中，她都是人们心目中完美的`美国青少年。

She fascinated him, both on and off stage.

不管是台上还是台下的她，都让他着迷。