a group of 9 bicycle riders in a group on a trail
They saw a bird on the trail.
Sometimes people do not see a bird while on the trail.
exists x1 x2 x3 x4 x5.(a_topic(x1) & of(x1,x2) & on(x2,x5) & n_trail(x5) & in(x2,x4) & n_group(x4) & n_rider(x2) & of(x2,x3) & n_bicycle(x3) & n_date(x2) & a_date_day_09(x2) & a_date_day_09(x2) & n_group(x1))
exists e1 x1 x2 x3.(n_trail(x3) & n_thing(x1) & Theme(e1,x2) & Actor(e1,x1) & v_see(e1) & on(x2,x3) & n_bird(x2))