IN, ON, AT
for an enclosed space
Use in when someone or something is inside something.
in - place as an area, state, city, ...
in Germany, in a city centre
in - inside a building
in a restaurant, in a musem
in - inside of something
in a little box, in the car
He lives in New York.
I work in this shopping centre.
She is waiting in the car.
Use on when one thing is attached to another or touching something else.
on - surface
on the table, on the floor
on - public transport (on the board)
on a plane, on a bus
on - a place as a point on a line
on the river, on the north coast
on - with directions
on the left, on the right
The book is on the desk.
I love traveling on a bus.
The hotel is on the river.
The shop is on the left.
for a point
Use at when someone or something is located at a specific point or location.
at - specific place
at home, at the bus
at - public places and institutions
at the station, at school
at - with "bottom", "back", "end", "front"
at the bottom of the page, at the top, at the side
Jane is waiting for you at the bus stop.
I was at the cinema yesterday.
Turn left at the end of the street.
What's the difference between these two sentences?
She's at the library.
the emphasis is on the her location and the type of place she has gone to.
She's in the library.
the emphasis is on the type of building she is in.
Both of these sentences are fine to answer the question "Where is she?"