A man is pulled behind a boat on a knee board while another doing the same begins to fall.
Two men are water boarding behind a boat.
pulled behind a boat is a rephrasing of water boarding.
exists e1 p1 x1 x2 x3 x4 x7.(n_same(x7) & exists e3 e2 p2 x5 x6.(Topic(e3,p2) & Actor(e3,x5) & v_begin(e3) & exists e4.(Actor(e4,x5) & v_fall(e4)) & Theme(e2,x7) & Actor(e2,x6) & v_do(e2) & (x5 = x6) & n_thing(x5)) & while(e1,p1) & behind(e1,x2) & on(x2,x3) & n_board(x3) & of(x3,x4) & n_knee(x4) & n_boat(x2) & Theme(e1,x1) & v_pull(e1) & n_man(x1))
exists e1 p1 x1 x2.(for(p1,e1) & behind(e1,x2) & n_boat(x2) & Actor(e1,x1) & v_board(e1) & exists x3.((x1 = x3) & n_water(x3)) & n_man(x1) & card_eq_2(x1))