Passengers boarding a train.
THe passengers board the train
The fact that passengers boarding a train does not imply that THe passengers board the train.
exists e1 x1 x2.(ne_nam_passengers(x1) & Theme(e1,x2) & Actor(e1,x1) & v_board(e1) & n_train(x2))
exists x1 x2 x3 x4.(a_topic(x1) & n_train(x4) & (x1 = x4) & n_board(x1) & of(x1,x3) & n_passenger(x3) & (x1 = x2) & ne_nam_the(x2))