Two men are working on a train.
The men are working on a house.
A train is not a house.
exists e1 x1 x2.(on(e1,x2) & n_train(x2) & Actor(e1,x1) & v_work(e1) & n_man(x1) & card_eq_2(x1))
exists e1 x1 x2.(n_man(x1) & on(e1,x2) & n_house(x2) & Actor(e1,x1) & v_work(e1))