Doctor is performing a surgery.
Doctor is performing heart surgery on a patient
The doctor may not specifically be performing heart surgery.
exists e1 x1 x2.(ne_nam_doctor(x1) & Theme(e1,x2) & Actor(e1,x1) & v_perform(e1) & n_surgery(x2))
exists e1 x1 x2 x3 x4.(ne_nam_doctor(x1) & on(e1,x4) & n_patient(x4) & Theme(e1,x2) & Actor(e1,x1) & v_perform(e1) & n_surgery(x2) & of(x2,x3) & n_heart(x3))