Ben bir deneme üzerinde çalışmak zorunda kaldım.
- I had to work on an essay.
Onun üzerinde çalışmak zorunda kalacağız.
- We'll have to work on that.
John's in the studio working on the plans for the new house.
Leave it to me. I'll try to work on the boss to give us the day off.
... "Clearly, you're working on something. Just finish it." ...
... We're not quite there yet, but we're working on it. ...