Need help tuning this Cursor

         CURSOR cenrollments (nperson_id number, nzone varchar2, nterm number)

        IS

           

 

select e.enrollment_id, o.offering_name||'-'|| s.name charge_name, sum(charge_amount)                            

from                                 

sss_student_enrollments e,

sss_stud_tut_charges c,

                          sss_sections s,

                          sss_offerings o,

                          esi_district_mapping dm

            where e.enrollment_id=c.enrollment_id

            and e.offering_id = o.offering_id

            and e.section_id = s.section_id

            and e.comb_id = dm.comb_id

            and c.person_id =nperson_id

            and e.term_id  = nterm

            and dm.zone_name = nzone

            group by e.enrollment_id, o.offering_name||'-'|| s.name;