Several people sitting in front of a house.
There are no people in front of the house.
Always several people will not sit in front of the house.
exists e1 s1 x1 x2 x3 x4.(a_topic(x1) & in(e1,x3) & of(x3,x4) & n_house(x4) & n_front(x3) & Actor(e1,x2) & v_sit(e1) & (x1 = x2) & n_people(x1) & a_several(s1) & Theme(s1,x1))
exists p1 x1 x2 x3.(n_house(x3) & in(p1,x2) & of(x2,x3) & n_front(x2) & -exists x4.((x1 = x4) & n_people(x4)))