Lots of people play in the water at the beach.
The people are in a pool.
The people in water can either be in the water at the beach or in a pool, but not at the same time.
exists e1 x1 x2 x3 x4.(n_beach(x4) & n_water(x3) & at(e1,x4) & in(e1,x3) & Actor(e1,x1) & v_play(e1) & of(x1,x2) & n_people(x2) & n_lot(x1))
exists p1 x1.(n_people(x1) & exists x2.(in(x1,x2) & n_pool(x2)))