The boys smiles underwater at the pool.
Kids are is in a pool.
in a pool is the same as at the pool
exists e1 x1 x2 x3.(n_pool(x3) & n_boy(x1) & at(e1,x3) & Theme(e1,x2) & Actor(e1,x1) & v_smile(e1) & n_underwater(x2))
exists e1 p1 x1 x2.(exists x3.(in(x1,x3) & n_pool(x3)) & Actor(e1,x2) & v_be(e1) & (x1 = x2) & n_kid(x1))