English prepositions of place: in, on.

IN = inside.

As a preposition of place, in means inside:

She stayed in the house all day.

There's a present in the box.

I've got it in my pocket.

There are places we can consider 3-dimensional like the street, the park, the woods, the mountains, the hills, the valley, the long grass, etc. We use in when refer a position in these places.

I X I

We went for a walk in the park.

There was a river in the valley.

The children hid in the long grass.

ON = attached to a 2-dimensional surface.

An object in contact with a 2-dimensional surface (but not inside something) is said to be on that surface. The surface can be flat or not flat. The orientation of that surface is not important.

Showing preposition on

There are some books on the table.

There was a large clock on the wall.

There was a spider on the ceiling.

David Beckam wrote his autograph on my football.

When we refer to the position of something and exterior 2-dimensional surfaces we also usually use on.

There was a lot of traffic on the road.

We sunbathed on the beach.

There was nobody on the football field.

There are exceptions. However, if you remember in for 3-dimensional places and on for 2-dimensional areas, usually you will be right.

Transport.

We can use in to emphasise that someone is inside a car, bus, train, aeroplane, boat, etc. if the person is inside. However, with the exception of "car", it is more common to use on to say someone is travelling by that transport:

We went on a ship around the Mediterranean.

I got on the bus at Trafalgar Square.

She's on a plane to the United States.

Can you get in the car, please?

Exercises: in, on as prepositions of place...

Also see: prepositions of place - in, at...