A man jumps while on a snowboard.
The man is performing a trick on the snowboard.
A man jumping on a snowboard does not men he is doing a trick.
exists e1 x1 x2.(on(e1,x2) & n_snowboard(x2) & r_while(e1) & Actor(e1,x1) & v_jump(e1) & n_man(x1))
exists e1 x1 x2 x3.(n_snowboard(x3) & n_man(x1) & on(e1,x3) & Theme(e1,x2) & Actor(e1,x1) & v_perform(e1) & n_trick(x2))