The man is being pulled behind a boat and doing tricks.
A man is doing tricks.
A man doing tricks is a man doing tricks.
exists e1 e2 x1 x2 x3.(n_man(x1) & Theme(e2,x3) & Actor(e2,x1) & v_do(e2) & n_trick(x3) & behind(e1,x2) & n_boat(x2) & Theme(e1,x1) & v_pull(e1))
exists e1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_do(e1) & n_trick(x2) & n_man(x1))