Teenagers are looking out the window of a bus.
Teens are standing in front of a school
One cannot be looking out the window and standing at the same time.
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 e1 x1 x2 x3.(in(e1,x2) & of(x2,x3) & n_school(x3) & n_front(x2) & Actor(e1,x1) & v_stand(e1) & n_teens(x1))