off and on

形容词 off and on:

1. intermittently stopping and starting
   同义词：fitful, interrupted, off-and-on

副词 off and on:

1. not regularly
   同义词：on and off

1. A device that automatically switches an electric lamp off and on, as in a commercial display sign.
   闪光装置如广告宣传告示上的一种自动点燃或熄灭电灯的装置
2. Recently it rained off and on every day.
   近来每天都在断断续续地下雨。
3. He has been writing to us off and on for several years.
   他断断续续地给我们写信已经有好几年了。
4. He only accepted the primary education off and on in his childhood.
   他小时候只断断续续地接受过初等教育。