The prepositions “in,” “at,” and “on” for indicating place and location.
The general rule :
1. “in” for an enclosed space.
2. “at” for a point.
3. “on” for a surface.
1. Usage of “in”
- Use “in” for spaces: “They always meet in a secret room [in a suburban hotel, in a parking lot, in a farm, in a ricefield].”
- Use “in” for names of specific land areas: “She lives in a quiet town [in Tagaytay, in Cavite, in Southern Tagalog, in the island of Palawan, in the Philippines, in Southeast Asia].
- Use “in” for bodies of water: “That kind of fish thrives in freshwater [in the river, in the lake, in streams, in the sea].”
- Use “in” for lines: “The registrants are in a row [in a line, in a queue].
2. Usage of “at”
- Use “at” to indicate points: “You’ll find us at the entrance [at the taxi stand, at the supermarket, at the intersection].”
- Use “at” for specific addresses, as in “She lives at 40 Lilac St.”
3. Usage of “on”
- Use “on” for names of streets, roads, avenues, and boulevards: “Her apartment is on San Pablo Street [on Ortigas Avenue, on Santolan Road, on Roxas Boulevard].”
- Use “on” for surfaces: “There’s a large stain on the floor [on the wall, on the ceiling, on the roof].”
The prepositions “in,” “at,” and “on” for indicating location.
Use “in” in these cases: “The children are in the kitchen [in the garden, in the car, in the library, in the class, in school]. (The article “the” is mandatory except for the fourth and last example.)
Use “at” in these particular cases: “She was at home [at the library, at the office, at school, at work] when we arrived.”
Use “on” in these particular cases: “They are on the plane [on the train, on the boat].”
Some locations, though, don’t need a preposition between them and the verb: “They sleep downstairs [inside, outside, downtown, upstairs, uptown].”