Teenagers are looking out the window of a bus.
Kids in a van
There can be either a bus or a van.
exists e1 x1 x2 x3.(n_window(x2) & out(e1,x2) & of(x2,x3) & n_bus(x3) & Actor(e1,x1) & v_look(e1) & n_teenager(x1))
exists x1 x2.(a_topic(x1) & in(x1,x2) & n_van(x2) & n_kid(x1))