Man is doing a trick while skiing on the lake.
A guy is practicing for the upcoming xgames.
Not everyone doing a trick is practicing for the xgames.
exists e1 x1 x2 x3 x4.(n_lake(x4) & on(e1,x4) & while(e1,x3) & n_skiing(x3) & Theme(e1,x2) & Actor(e1,x1) & v_do(e1) & n_trick(x2) & n_man(x1))
exists e1 s1 x1 x2.(n_xgame(x2) & a_upcoming(s1) & Theme(s1,x2) & for(e1,x2) & Actor(e1,x1) & v_practice(e1) & n_guy(x1))