A waterskier is waving at the camera happily.
A man is participating in a contest.
Not all water-skier's are men. One is not necessarily participating in a contest just because they are skiing.
exists e1 s1 x1 x2.(n_camera(x2) & a_happily(s1) & Manner(e1,s1) & at(e1,x2) & Actor(e1,x1) & v_wave(e1) & n_waterskier(x1))
exists e1 x1 x2.(in(e1,x2) & n_contest(x2) & Actor(e1,x1) & v_participate(e1) & n_man(x1))