Two people ride the train.
The train is long
Not all trains are long.
exists e1 x1 x2.(n_train(x2) & Theme(e1,x2) & Actor(e1,x1) & v_ride(e1) & n_people(x1) & card_eq_2(x1))
exists s1 x1.(n_train(x1) & Theme(s1,x1) & a_long(s1))