Men sitting on an army tank.
The men are army soldiers.
Just because men are sitting on an army tank, it does not follow that they are soldiers. They could be at a museum, or protestors, or actors in a film.
exists e1 x1 x2 x3 x4.(a_topic(x1) & on(e1,x3) & n_tank(x3) & of(x3,x4) & n_army(x4) & Actor(e1,x2) & v_sit(e1) & (x1 = x2) & n_man(x1))
exists p1 x1.(n_man(x1) & exists x2 x3.((x1 = x2) & n_soldier(x2) & of(x2,x3) & n_army(x3)))