A snowboarder is doing a trick.
The snowboarder sat by the fireplace.
One does not snowboard by the fireplace.
exists e1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_do(e1) & n_trick(x2) & n_snowboarder(x1))
exists e1 x1 x2.(n_fireplace(x2) & n_snowboarder(x1) & by(e1,x2) & Actor(e1,x1) & v_sit(e1))