A man in a gray shirt is hitting a tennis ball.
A man playing tennis.
A man hitting a tennis ball is not necessarily playing tennis.
exists e1 s1 x1 x2 x3 x4.(Theme(e1,x3) & Actor(e1,x1) & v_hit(e1) & n_ball(x3) & of(x3,x4) & n_tennis(x4) & in(x1,x2) & n_shirt(x2) & a_gray(s1) & Theme(s1,x2) & n_man(x1))
exists e1 x1 x2 x3.(a_topic(x1) & Theme(e1,x3) & Actor(e1,x2) & v_play(e1) & n_tennis(x3) & (x1 = x2) & n_man(x1))