Should I use the proposition at or in?
Often the difference between at and in is this:
at = general
I'm at work (the idea that I am busy and working)
I'm at the beach (I'm sunbathing, swimming, maybe leaving the sand to have a drink at a bar)
in = physical
I'm in the office. (I am physically in a specific location)
I'm in the classroom (I am physically in a specific location)
However, sometimes you can use either. Abstractly, you can say I'm in OR at university and it means the same = that is your occupation or that is physically where you are.
