Two people ride the train.
A train ride.
People ride the train so it must be a train ride.
exists e1 x1 x2.(n_train(x2) & Theme(e1,x2) & Actor(e1,x1) & v_ride(e1) & n_people(x1) & card_eq_2(x1))
exists x1 x2.(a_topic(x1) & n_ride(x1) & of(x1,x2) & n_train(x2))