The child is walking through straw.
The child is outside.
The child can be walking through straw only when he is outside.
exists e1 x1 x2.(n_child(x1) & through(e1,x2) & n_straw(x2) & Actor(e1,x1) & v_walk(e1))
exists s1 x1.(n_child(x1) & Theme(s1,x1) & a_outside(s1))