A teenage girl walks past another with a cellphone.
Nobody is walking.
either a girl walks or nobody does
exists e1 s1 x1 x2 x3 x4.(for(e1,s1) & Theme(s1,x1) & a_past(s1) & Theme(e1,x3) & Actor(e1,x1) & v_walk(e1) & with(x3,x4) & n_cellphone(x4) & n_thing(x3) & n_girl(x1) & of(x1,x2) & n_teenage(x2))
-exists e1 x1.(Actor(e1,x1) & v_walk(e1) & n_person(x1))