A man in a wetsuit is surfing on a green surfboard.
A man is surfing while his friends watch from the beach.
surfboard doesn't always mean  watch from the beach.
exists e1 s1 x1 x2 x3.(on(e1,x3) & n_surfboard(x3) & a_green(s1) & Theme(s1,x3) & Actor(e1,x1) & v_surf(e1) & in(x1,x2) & n_wetsuit(x2) & n_man(x1))
exists e1 e2 x1 x2 x3 x4 x5.(n_beach(x5) & from(e2,x5) & Theme(e2,x4) & Actor(e2,x1) & v_watch(e2) & n_thing(x4) & while(e1,x3) & n_friend(x3) & of(x3,x1) & n_male(x1) & Actor(e1,x2) & v_surf(e1) & (x1 = x2) & n_man(x1))