3 sentences

1. 雨断断续续地下了一整天。

   yǔ duàn​duàn​xù​xù de xià le yī​zhěng​tiān.

   It rained on and off all day.

   Source: Tatoeba

2. 我断断续续地在网上约会了15年。

   wǒ duàn​duàn​xù​xù de zài wǎng​shàng yuē​huì le15 nián.

   I have done online dating on and off for 15 years.

   Source: CCMatrix

3. 他断断续续地给我们写信已经有好几年了。

   tā duàn​duàn​xù​xù de gěi wǒ​men xiě xìn yǐ​jing yǒu hǎo​jǐ​nián le.

   He has been writing to us off and on for several years.

   Source: UM-Corpus: Education