1) We use the preposition in to indicate something physically inside a place.
- See you in the classroom!
- I like swimming in the sea.
- We meet every day in that bar at ten o'clock.
2) We use the preposition on to indicate the position on a surface of something.
- Your mobile is on the television.
- There is an old big tree on the top of the hill.
- I like surfing on the waves.
3) We use the preposition at to indicate a reference point.
- See you at the Cinema Luxor.
- The shop is at the top of the steps.
- They have a little house at the end of the street.
1) We use the preposition in for years, seasons, months and moments of the day.
|in||the twentieth century|
|the morning/ the evening|
- I usually go to Sardinia in the summer.
- They worked in a restaurant in 1998.
2) We use the preposition on for completed dates, days of the week, holiday days.
- I often stay with my parents on Christmas Day.
- We usually play tennis on Sunday.
3) We use the preposition at for a reference point in time.
- See you at ten o'clock near the school.
- What do you usually do at night?