Sitting on a doorstep talking.
Someone is sitting on a doorstep.
"Sitting" means someone is sitting.
exists e1 e2 x1 x2 x3.(on(e1,x2) & Actor(e2,x3) & v_talking(e2) & (x2 = x3) & n_doorstep(x2) & Actor(e1,x1) & v_sit(e1) & n_thing(x1))
exists e1 x1 x2.(on(e1,x2) & n_doorstep(x2) & Actor(e1,x1) & v_sit(e1) & n_person(x1))