1.On and off for about three years.

断断续续差不多三年了。

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

他断断续续学习了75年。

3.Oh, about two years on and off.

断断续续有两年了。

4.The car engine goes on and off?

就凭汽车发动又停下？

5.The bird's lights blink on and off.

个燕子标志灯一闪一闪。

6.A timer turns your lights on and off.

器可以为你开关电灯。

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

“1”和“0”代表晶体管开关状态。

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

另外，它们非常容易开关。

9.A small timer microprocessor turns the pumps on and off.

一个小型微处理器打开和关闭泵。

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

我断断续续在了九年。

11.He's served on, and off, and on again since then.

此后，他经历了当选、连任失败和再次当选。

12.It can turn the lights in your home on and off.

它可以打开和关闭你家灯光。

13.You can't turn it on and off whenever you want.

不是你意愿能够控制。

14.Did it move or do they just blink on and off?

它动了吗？还是它们只是忽明忽暗？

15.He did that on and off for the next four years.

接下来四年，他断断续续地样生活。

16.Or users can turn it on and off when they want.

还可以由用户自行打开或关闭。

17.There's switches so you can turn things on and off.

驱动器还有开关， 让你能够实现启动和关闭功能。

18.The past few years have been spent on and off anti-depressants.

过去几年，他一直在断断续续地服用抗抑郁药物。

19.And finally, here she says that, " I was teaching on and off."

最后，她说，I was teaching on and off。

20." It doesn't just turn the lights on and off, " said Ron.

“它作用并不只是开灯和关灯，”罗恩说道。