We useat:
to refer to a position or location which we see as a point:
I was sittingatmy desk.
to talk about locations at companies, workplaces when we see them as a place of activity:
How many people are workingatMicrosoft?
to refer to activities which involve a group of people:
Were youatLisa’s party?(alsoat the cinema, at the theatre)
withschool/college/university:
She always did wellatschool.
to refer to an address:
They once livedatnumber 12 South George’s Street.
to talk about public places where we get treatments, such as a hairdresser’s or doctor’s surgery:
I can’t meetatfour. I’ll beatthe hairdresser’s until five.
to refer to most shops:
Look what I boughtatthe butcher’s today.
We useon:
to refer to a position on any surface:
I know I left my walletonthe table.
to describe a position along a road or river or by the sea or by a lake:
Dublin isonthe east coast of Ireland.
to talk about a floor in a building:
They liveonthe 15th floor!
to talk about being physically on public transport:
I wasonthe train when she phoned.(but to talk about ways of travelling, we useby:I went to Romebytrain.)
We usein:
to talk about locations within a larger area:
I know my book is somewhereinthis room. Can anyone see it?
to talk about workplaces when we see them as a physical location:
She worksinan open-plan office.(but we useonwhen we talk about a farm:I’ve always wanted to workona farm.)
withclass:
He found it difficult to concentrateinclass.
See also:
At,onandin(time)