A boy is sitting on a black boat with two flags on long poles.
The boy is waterskiing.
Water skiing implies that the boy is out of the boast as opposed to sitting on it.
exists e1 s1 s2 x1 x2 x3 x4.(with(e1,x3) & on(x3,x4) & n_pole(x4) & a_long(s2) & Theme(s2,x4) & n_flag(x3) & card_eq_2(x3) & on(e1,x2) & n_boat(x2) & a_black(s1) & Theme(s1,x2) & Actor(e1,x1) & v_sit(e1) & n_boy(x1))
exists e1 x1.(n_boy(x1) & Actor(e1,x1) & v_waterskie(e1))