A child is pushing a tire.
A child is riding a bicycle.
Pushing a tire is not possible while riding a bicycle.
exists e1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_push(e1) & n_tire(x2) & n_child(x1))
exists e1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_ride(e1) & n_bicycle(x2) & n_child(x1))