work at : physical location이 뒤에 붙음
I'm working at a bank, We work at the same place, He worked at a company for thirty years 등
work for : 고용된 곳(사람/단체)가 뒤에 붙음
I'm working for a bank, I work for a company called~
work in : 일하는 분야, 직무가 붙음
I'm working in a banking industry, I work in the Sales departement 등 #오늘의영어표현