A man in a blue shirt is tossing a football.
a man playing catch
Tossing a football does not necessarily mean playing catch.
exists e1 s1 x1 x2 x3.(Theme(e1,x3) & Actor(e1,x1) & v_toss(e1) & n_football(x3) & in(x1,x2) & n_shirt(x2) & a_blue(s1) & Theme(s1,x2) & n_man(x1))
exists x1 x2 x3.(a_topic(x1) & n_catch(x1) & of(x1,x3) & n_playing(x3) & of(x1,x2) & n_man(x2))