On and off for about three years.

断断续续差不多三年了。

He studied for his degree on and off for 75 years.

他断断续续学习了75年的时间。

The car engine goes on and off?

就凭汽车发动又停下？

The bird's lights blink on and off.

这个燕子标志灯一闪一闪的。

A timer turns your lights on and off.

定时器可以为你定时开关电灯。

Ones and zeroes representing the on and off states of the transistor.

“1”和“0”代表晶体管的开关状态。

So I was teaching on and off for several years.

我断断续续地教了几年书。

Plus, they're super easy to toggle on and off.

另外，它们非常容易开关。

A small timer microprocessor turns the pumps on and off.

一个小型定时微处理器打开和关闭泵。

I've been living here on and off for nine years.

我断断续续在这里住了九年。