Someone is running on a track at sunset.
A person runs on the track.
someone is  a person. running refers to runs.
exists e1 x1 x2 x3.(at(e1,x3) & n_sunset(x3) & on(e1,x2) & n_track(x2) & Actor(e1,x1) & v_run(e1) & n_person(x1))
exists e1 x1 x2.(n_track(x2) & on(e1,x2) & Actor(e1,x1) & v_run(e1) & n_person(x1))