A large group of people are riding on a blue roller coaster.
People ride.
A large group of people are people. If they ride, they are riding.
exists e1 s1 s2 x1 x2 x3 x4.(on(e1,x3) & n_coaster(x3) & of(x3,x4) & n_roller(x4) & a_blue(s2) & Theme(s2,x3) & Actor(e1,x1) & v_ride(e1) & of(x1,x2) & n_people(x2) & n_group(x1) & a_large(s1) & Theme(s1,x1))
exists e1 x1.(Actor(e1,x1) & v_ride(e1) & n_people(x1))