Doctor is performing a surgery.
Doctor is working on a patient
the doctor is performing a surgery on a patient
exists e1 x1 x2.(ne_nam_doctor(x1) & Theme(e1,x2) & Actor(e1,x1) & v_perform(e1) & n_surgery(x2))
exists e1 x1 x2.(ne_nam_doctor(x1) & on(e1,x2) & n_patient(x2) & Actor(e1,x1) & v_work(e1))