An orchestra of about 30 people are practicing on the stage of what appears to be an auditorium full of green chairs.
A couple of people in green chairs watch an orchestra practice.
An auditorium can be empty, it does not necessarily have to have a couple of people seated in its chairs.
exists e1 x1 x2 x3.(n_stage(x3) & exists e2 p1 x4.(n_thing(x4) & on(e1,x3) & of(x3,x4) & Topic(e2,p1) & Actor(e2,x4) & v_appear(e2) & exists p2 s1 s2 x5 x6 x7.((x4 = x5) & of(s1,x7) & n_chair(x7) & a_green(s2) & Theme(s2,x7) & Theme(s1,x6) & a_full(s1) & (x5 = x6) & n_auditorium(x5))) & Actor(e1,x1) & v_practice(e1) & of(x1,x2) & n_people(x2) & n_date(x2) & a_date_day_30(x2) & a_date_day_30(x2) & r_about(x2) & n_orchestra(x1))
exists e1 s1 x1 x2 x3 x4 x5.(Theme(e1,x4) & Actor(e1,x1) & v_watch(e1) & n_practice(x4) & of(x4,x5) & n_orchestra(x5) & in(x1,x3) & n_chair(x3) & a_green(s1) & Theme(s1,x3) & of(x1,x2) & n_people(x2) & n_couple(x1))