A chef cooks something in a skillet.
A cook is preparing fish in a skillet.
A skillet can be used for other purposes that do not include preparing fish.
exists e1 x1 x2 x3.(Theme(e1,x2) & Actor(e1,x1) & v_cook(e1) & in(x2,x3) & n_skillet(x3) & n_thing(x2) & n_chef(x1))
exists e1 x1 x2 x3.(in(e1,x3) & n_skillet(x3) & Theme(e1,x2) & Actor(e1,x1) & v_prepare(e1) & n_fish(x2) & n_cook(x1))