English prepositions of place: in, at

AT = near or inside.

When we give the location of a thing or a person, we can generalise and say they are perhaps near a place or inside a place. When we generalise like this, we use at. The square below is a discotheque and X is Mary:

or,

Mary's at the discotheque. (She's perhaps inside or outside smoking a cigarette.)

Steve's at work. (He's in or near his office having a coffee.)

John's at home. (He's in his house or outside in the garden.)

We can also use at to generalise about location when we talk about open places like parks, the beach, etc.

They're at the beach this weekend. (In that area but not necessarily on the beach.)

She's at the park. (In the area of the park.)

IN = always inside.

When we want to be more specific, we use in to always refers to something or somebody "inside" a place. The square below is the discotheque and X is Mary.

Mary is in the discotheque. (inside)

Steve is in the office. (inside)

John is in his house. (inside)

In can also refer to the location in a place which is an open area but has three dimensions like the street (the houses on each side), the park (the trees in the park), etc:*

The children are playing in the street.

There's a beautiful statue in the park.

but...

On the beach. (It's a flat area of two dimensions.)

*This rule can have exceptions, for example, "in the desert".

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

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