A tennis player in mid-swing at a match.
The tennis player is playing
The tennis player is not necessarily playing if they are at a match.
exists x1 x2 x3 x4.(a_topic(x1) & in(x1,x3) & at(x3,x4) & n_match(x4) & n_mid-swing(x3) & n_player(x1) & of(x1,x2) & n_tennis(x2))
exists e1 x1 x2.(n_player(x1) & of(x1,x2) & n_tennis(x2) & Actor(e1,x1) & v_play(e1))