A repairman is working on a train.
A man is working on a race car.
There is either a repairman working on a train or a man working on a race car.
exists e1 x1 x2.(on(e1,x2) & n_train(x2) & Actor(e1,x1) & v_work(e1) & n_repairman(x1))
exists e1 x1 x2 x3.(on(e1,x2) & n_car(x2) & of(x2,x3) & n_race(x3) & Actor(e1,x1) & v_work(e1) & n_man(x1))