A person in a hard hat is doing some work on a train track.
A construction worker builds a new mountain railroad.
The person is not necessarily a construction worker, even though he is wearing a hard hat. The person is not necessarily building a mountain railroad, even though he is doing work on a train track.
exists e1 s1 x1 x2 x3 x4 x5.(Theme(e1,x3) & Actor(e1,x1) & v_do(e1) & on(x3,x4) & n_track(x4) & of(x4,x5) & n_train(x5) & n_work(x3) & in(x1,x2) & n_hat(x2) & a_hard(s1) & Theme(s1,x2) & n_person(x1))
exists e1 s1 x1 x2 x3 x4.(Theme(e1,x3) & Actor(e1,x1) & v_build(e1) & n_railroad(x3) & of(x3,x4) & n_mountain(x4) & a_new(s1) & Theme(s1,x3) & n_worker(x1) & of(x1,x2) & n_construction(x2))