''to turn in' means to go to bed.
- It's very late, I'm going to turn in.
- Come on, let's turn in and get a good night's sleep.
'to turn in' also means to produce results, usually very good results.
- The company turned in it's best results yet. Turnover is up 20% on last quarter.
- All of the students turned in excellent work this term.
'to turn into' means to change and become something different.
- If we are not careful, this little setback could turn into a major problem.
- The old warehouses along the river have been turned into very expensive flats.
'to turn off' means to use a switch to stop something working.
- Before you go up to bed, remember to turn the TV off.
- Don't turn off the light in the hall. I usually leave it on all night.
'to turn off' also means to leave a road to travel on a different one.
- After a couple of miles, you turn off the main road and go down a little lane.
- You turn off the motorway at junction 6 and follow the signs to the airport.
'to turn on' means to use a switch to start something working.
- First thing I do in the morning, is turn on my computer and the coffee machine.
- It was dark in the house when I went in. Nobody had turned the lights on.
'to turn on' also means to attack or criticise someone.
- They had always supported the Prime Minister but now they have turned on him.
- That race of dog is very unpredictable, they can suddenly turn on you.
'to turn out' means to have a particular result.
- We had a very good afternoon. The weather turned out well.
- I was so pleased with the food. Even the cakes turned out perfectly.
'to turn out' also means to produce, often in big quantities.
- They turn out hundreds every day which they sell all over the country.
- The new machines in production mean we can turn out twice as many at half the price.
'to turn out' also means people go and participate at or watch an event.
- Thousands turned out to see the Queen when she opened the new hospital.
- A very high percentage of voters turned out to vote at the last elections.