There are numerous people sitting in gray chairs.
Lots of people sit in grey chairs while they watch butterflies.
Watching butterflies is a single activity that might be performed while sitting in chairs.
exists p1 x1 e1 s1 s2 x2 x3 x4.((x1 = x2) & in(e1,x4) & n_chair(x4) & a_gray(s2) & Theme(s2,x4) & Actor(e1,x3) & v_sit(e1) & (x2 = x3) & n_people(x2) & a_numerous(s1) & Theme(s1,x2))
exists e1 p1 x1 x2 x3 x4.(exists e2 x5.(Theme(e2,x5) & Actor(e2,x1) & v_watch(e2) & n_butterfly(x5)) & n_thing(x1) & while(e1,p1) & in(e1,x3) & n_chair(x3) & of(x3,x4) & n_grey(x4) & Actor(e1,x1) & v_sit(e1) & of(x1,x2) & n_people(x2) & n_lot(x1))