A family or a group of friends are having a picnic in what appears to be a park.
A family are having a picnic of sandwiches.
We have no idea if they are having a picnic of sandwiches, they could be eating anything.
(exists x1 x2.(exists e2 e1 p1 x3.(n_thing(x3) & Theme(e2,x2) & Actor(e2,x1) & v_have(e2) & in(x2,x3) & Topic(e1,p1) & Actor(e1,x3) & v_appear(e1) & exists p2 x4.((x3 = x4) & n_park(x4))) & n_picnic(x2) & n_family(x1)) | exists x5 x6 x7.(exists e3 e4 p3 x8.(n_thing(x8) & Theme(e4,x7) & Actor(e4,x5) & v_have(e4) & in(x7,x8) & Topic(e3,p3) & Actor(e3,x8) & v_appear(e3) & exists p4 x9.((x8 = x9) & n_park(x9))) & n_picnic(x7) & of(x5,x6) & n_friend(x6) & n_group(x5)))
exists e1 x1 x2 x3.(Theme(e1,x2) & Actor(e1,x1) & v_have(e1) & of(x2,x3) & n_sandwich(x3) & n_picnic(x2) & n_family(x1))