Men building a sand castle in shallow water.
Two men are building a sand castle on the beach.
Any number of men can build a sand castle and there is no reason to assume only two men are building the sand castle. Sand castles can be built in shallow water found in places other than a beach.
exists e1 s1 x1 x2 x3 x4 x5.(a_topic(x1) & in(e1,x5) & n_water(x5) & a_shallow(s1) & Theme(s1,x5) & Theme(e1,x3) & Actor(e1,x2) & v_build(e1) & n_castle(x3) & of(x3,x4) & n_sand(x4) & (x1 = x2) & n_man(x1))
exists e1 x1 x2 x3 x4.(n_beach(x4) & on(e1,x4) & Theme(e1,x2) & Actor(e1,x1) & v_build(e1) & n_castle(x2) & of(x2,x3) & n_sand(x3) & n_man(x1) & card_eq_2(x1))