People sitting on the grass with a black and white dog.
There is a dog present.
'' People sitting on the grass with a black and white dog '' is a  rephrasing of '' there is a dog present.''
exists e1 s1 s2 x1 x2 x3 x4.(n_grass(x3) & a_topic(x1) & with(e1,x4) & n_dog(x4) & a_white(s2) & Theme(s2,x4) & a_black(s1) & Theme(s1,x4) & on(e1,x3) & Actor(e1,x2) & v_sit(e1) & (x1 = x2) & n_people(x1))
exists p1 x1 x2 x3.((x1 = x2) & n_present(x2) & of(x2,x3) & n_dog(x3))