A couple are dancing while others are watching a concert in a bandstand.
Several people are sitting while waiting for the music to start.
People cannot be watching a concert and waiting for the music to start at the same time.
exists e1 p1 x1.(exists e2 x2 x3 x4.(in(e2,x4) & n_bandstand(x4) & Theme(e2,x3) & Actor(e2,x2) & v_watch(e2) & n_concert(x3) & -(x2 = x1) & n_person(x2)) & n_person(x1) & while(e1,p1) & Actor(e1,x1) & v_dance(e1) & n_couple(x1))
exists e2 e1 p1 s1 x1 x2.(n_music(x2) & while(e1,e2) & Topic(e2,p1) & Actor(e2,x1) & v_wait(e2) & exists e3.(Actor(e3,x2) & v_start(e3)) & Actor(e1,x1) & v_sit(e1) & n_people(x1) & a_several(s1) & Theme(s1,x1))