The main ones are: as - at - for - with - in - on -under. The different meanings and uses are quite easy to understand. but it might take some practice to get them right. Here are some examples: I work as a nurse, as an accountant. I work at a hospital, I work at a department store. I work at XYZ. (Name of the business or workplace) I work for Macy's (name of store). Can use at or for here. I work for a good boss, for Ms Smith. Cannot use at here. I work in the city, in a high rise building. I work in New York, in Moscow (name of place, country etc) I'm working on an assignment for my university course, on a project in Europe. I work under a very strict manager who gives me too much work. I work with a nice group of people

Thanks. The first meaning which comes to my mind is 'to be employed by'. I'll search the others.

Maybe it's easier to search for "phrasal verbs work". Even the first few which come to my mind need lengthy explanations!