work on somebody/something phrasal verb ( see also ↑ work )
1 . to spend time working in order to produce or repair something:
He has spent the last two years working on a book about childcare.
Every weekend you see him working on his car.
2 . to try very hard to improve or achieve something:
A trainer has been brought in to work on her fitness.
work on doing something
We need to work on ensuring that the children feel safe and confident.
3 . to try continuously to influence someone or persuade them to do something:
You leave him to me. I’ll work on him.