A group of men are changing the shells on a cannon.
The men are photographers.
Just because they are changing shells on a cannon, it cannot be assumed that they are photographers.
exists e1 x1 x2 x3 x4.(n_shell(x3) & on(e1,x4) & n_cannon(x4) & Theme(e1,x3) & Actor(e1,x1) & v_change(e1) & of(x1,x2) & n_man(x2) & n_group(x1))
exists p1 x1.(n_man(x1) & exists x2.((x1 = x2) & n_photographer(x2)))