'to turn over' means to move yourself or something so that you or it are facing in the opposite direction.
- I'd like to see the other side. Can you turn it over, please?
- Turn over and lie on your back.
'to turn over' means to give something to someone in authority.
- During the investigation all the documents were turned over to the police.
- They were turned over to the immigration authorities as soon as they landed at the airport.
'to turn round' means to make a business profitable after an unsuccessful period.
- It lost a lot of money last year but the new management have turned it round.
- All political parties promise to turn the economy round if elected but they never do!
'to turn round' also means to change the way something is expressed or considered.
- Let's turn that question round and look at it from a different point of view.
- He always turns what I say round to make me look stupid.
'to turn to' someone means to ask them for help or sympathy.
- I need help and I don't know who to turn to.
- She doesn't seem to have any friends to turn to when she needs help.
'to turn to' can also mean to focus on something.
- Let's turn our attention to the question of finance next.
- Let's move on and turn to an important problem we are facing – drop in sales.
'to turn up' means to increase the amount of something, especially heat or volume.
- It is cold in here. Can you turn up the heating, please?
- I can't hear it. Can you turn it up, please?
'to turn up' also means to arrive at a place.
- He finally turned up at my house half an hour late.
- You don't need to book. You can just turn up and buy a ticket at the door.
'to turn up' can also mean that someone or something arrives when not expected.
- You'll find a job. I'm sure something will turn up quite soon.
- Jane didn't call to ask if she could come, she just turned up and stayed the weekend.