A young by sits on a carpeted staircase.
The boy is eating on the staircase.
The fact that the boy sits on a carpeted staircase doesn't imply that he's eating on it.
exists s1 x1 x2 x3.(a_topic(x1) & by(x1,x2) & on(x2,x3) & n_staircase(x3) & a_carpeted(s1) & Theme(s1,x3) & n_sit(x2) & n_young(x1))
exists e1 x1 x2.(n_staircase(x2) & n_boy(x1) & on(e1,x2) & Actor(e1,x1) & v_eat(e1))