I want to know some things about grad studies: i) What does it mean "part time student" or "full time student"?. I am going to work as GSR, and I think it has to do with it, hasn't it? ii) How much free am I to choose the grad courses I want? iii) How many courses do you have to complete? iv) could I choose as many courses as I want? v) and what's "a unit"?. Is a unit a course, or is what in europe we call "credit"? Thanks! I will have to discuss this stuff with my advisor, but I prefer to know something about what the hell he is talking me about.