The snowboarder is sitting down.
A person is seated.
A snowboarder is a person and sitting down means to be seated.
exists e1 s1 x1.(n_snowboarder(x1) & a_down(s1) & Manner(e1,s1) & Actor(e1,x1) & v_sit(e1))
exists e1 x1.(Theme(e1,x1) & v_seat(e1) & n_person(x1))