Various people sitting on a subway.
People on the bus
People cannot be sitting on a subway and a bus at the same time.
exists e1 s1 x1 x2 x3.(a_topic(x1) & on(e1,x3) & n_subway(x3) & Actor(e1,x2) & v_sit(e1) & (x1 = x2) & n_people(x1) & a_various(s1) & Theme(s1,x1))
exists x1 x2.(n_bus(x2) & a_topic(x1) & on(x1,x2) & n_people(x1))