People on a bus, riding and looking out the windows.
People are on an airplane.
One cannot be on a bus and on an airplane simultaneously.
exists e1 x1 x2 x3 x4 x5 x6.(n_window(x6) & a_topic(x1) & on(x1,x2) & rel(x2,x3) & subset_of(e1,x3) & out(e1,x6) & Actor(e1,x5) & v_look(e1) & n_thing(x5) & subset_of(x4,x3) & n_riding(x4) & n_bus(x2) & n_people(x1))
exists p1 x1.(exists x2.(on(x1,x2) & n_airplane(x2)) & n_people(x1))