A railroad work crew performs maintenance on railroad tracks.
A man is fixing a radio.
A man that performs maintenance on railroad tracks cannot be fixing a radio at the same time.
exists e1 x1 x2 x3 x4 x5 x6.(Theme(e1,x4) & Actor(e1,x1) & v_perform(e1) & on(x4,x5) & n_track(x5) & of(x5,x6) & n_railroad(x6) & n_maintenance(x4) & n_crew(x1) & of(x1,x3) & n_work(x3) & of(x1,x2) & n_railroad(x2))
exists e1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_fix(e1) & n_radio(x2) & n_man(x1))