A person is sitting under a purple umbrella on the beach.
A person brought his family to the beach.
It's a bit unclear as to whether the person's family is sitting under the umbrella also, but the additional information that he brought his family to the beach with him indicates that he is not alone at the beach.
exists e1 s1 x1 x2 x3.(n_beach(x3) & on(e1,x3) & under(e1,x2) & n_umbrella(x2) & a_purple(s1) & Theme(s1,x2) & Actor(e1,x1) & v_sit(e1) & n_person(x1))
exists e1 x1 x2 x3.(n_beach(x3) & to(e1,x3) & Theme(e1,x2) & Actor(e1,x1) & v_bring(e1) & n_family(x2) & of(x2,x1) & n_male(x1) & n_person(x1))