A repairman is working on a train.
A man is repairing a steam engine.
It cannot be inferred that the man working on a train is repairing a steam engine.
exists e1 x1 x2.(on(e1,x2) & n_train(x2) & Actor(e1,x1) & v_work(e1) & n_repairman(x1))
exists e1 x1 x2 x3.(Theme(e1,x2) & Actor(e1,x1) & v_repair(e1) & n_engine(x2) & of(x2,x3) & n_steam(x3) & n_man(x1))