Prepositions

a) At / on / in (Time)

We use:

At		Time
On		Days & Dates
In		Months, years & seasons

Examples:

I start school at five o'clock (time)

I go to the tennis club on Fridays (days)

My birthday is on the 13th of August (dates)

I usually go on holiday in August (months)

I was born in 1980 (years)

In Summer, I like going swimming (seasons)

Expressions with "at":

At night / At the weekend / At Christmas / At the same time / At the moment

Expressions with "in":

In the morning (s) / In the afternoon (s) / In the evening (s) / In a few minutes / In six months

We do not use "at / on / in" before "last / next / this / every":

We'll see you next Friday

I went on holiday last summer

b) In / at & on (place)

We use:

In		At		On
-		-
A country		A specific place		Surfaces
Geographic region		An exact address		Buildings
A city, town or village		Public places
A road or street		Shops or workplaces
Inside a room, building, place		Social events
		Building

Examples:

In Spain the people speak Castilian (country)

We took these photos in the mountains (geographical region)

I used to live in London (city)

Selfridges is in Oxford Street (street)

It is very hot in the living room (room)

I was at my friend's house (specific place)

I live at 32 Bradgate, Cuffley, Herts (address)

We'll meet at the station (public place)

James is at the supermarket (shops)

They were at the theatre yesterday (social event)

Does this train stop at Paddington? (place)

Last night I ate at a restaurant (building)

I am lying on an island (surface)

The fly is on the ceiling (surface)

I am sitting on the floor (surface)

Expressions with "in":

In a line / in a queue / in a street / In a picture / In the world / in the sky / In a book / In a letter / In a car (taxi)

I was waiting in the queue for two hours

I read it in a book

I got in the car

Expressions with "on":

On the right (left) / On the first (second, etc.) floor / On the menu / On the coast / On a bus (train, plane, ship, bicycle, horse)

My house is the first on the left and I live on the third floor

I got on the bus

Expressions with "at":

At home (work, school, university, college) / At somebody's house / At the station (airport) / At sea

We were at sea for 3 months