大一:freshman
大二:sophomore
大三:junior
大四:senior
大学毕业生:graduate or a graduate of college
研究生:a gradiate of student or master or a postgraduate student
博士生:a candidate for a doctor's degree
博士:doctor
博士后:postdoctoral
学士学位:the degree of Bachelor of Arts(Science....)
硕士学位:master's degree