In which of these sentences can we put the object before the preposition or particle?

1. If you look carefully, you can make out a person in the background oft he photograph.
2. I always look after my sister’s dog when she’s on holiday.
3. I get on with all my classmates.
4. I came across this report while I was clearing out my desk.
5. I always put off my homework until later – and I shouldn’t!
6. I hear that Robbie has taken up a new sport.