Runners in a big city marathon.
A group of people are riding bicycles.
Riding bicycle and running are different activities.
exists s1 x1 x2 x3.(a_topic(x1) & in(x1,x2) & n_marathon(x2) & of(x2,x3) & n_city(x3) & a_big(s1) & Theme(s1,x2) & n_runner(x1))
exists e1 x1 x2 x3.(Theme(e1,x3) & Actor(e1,x1) & v_ride(e1) & n_bicycle(x3) & of(x1,x2) & n_people(x2) & n_group(x1))