A skier navigates his path downhill.
The skier is a professional.
A skier can be navigating their path downhill without being a professional.
exists e1 x1 x2 x3.(Time(e1,x3) & n_downhill(x3) & Theme(e1,x2) & Actor(e1,x1) & v_navigate(e1) & n_path(x2) & of(x2,x1) & n_male(x1) & n_skier(x1))
exists p1 x1.(n_skier(x1) & exists x2.((x1 = x2) & n_professional(x2)))