A group of people stand on a grassy field.
A group of people are sitting in the bleachers
People who stand on a grassy field cannot also be sitting in the bleachers at the same time as that's two different actions being performed on two different surfaces.
exists e1 s1 x1 x2 x3.(on(e1,x3) & n_field(x3) & a_grassy(s1) & Theme(s1,x3) & Actor(e1,x1) & v_stand(e1) & of(x1,x2) & n_people(x2) & n_group(x1))
exists e1 x1 x2 x3.(n_bleacher(x3) & in(e1,x3) & Actor(e1,x1) & v_sit(e1) & of(x1,x2) & n_people(x2) & n_group(x1))