A boy travels through a brick walkway.
A boy is with a girl
A boy who travels is not always with a girl.
exists e1 x1 x2 x3.(through(e1,x2) & n_walkway(x2) & of(x2,x3) & n_brick(x3) & Actor(e1,x1) & v_travel(e1) & n_boy(x1))
exists p1 x1.(exists x2.(with(x1,x2) & n_girl(x2)) & n_boy(x1))