Question: What are the first names, office locations of all lecturers who have taught some course?
SQL: SELECT T2.emp_fname ,  T4.prof_office ,  T3.crs_description FROM CLASS AS T1 JOIN employee AS T2 ON T1.prof_num  =  T2.emp_num JOIN course AS T3 ON T1.crs_code  =  T3.crs_code JOIN professor AS T4 ON T2.emp_num  =  T4.emp_num