Bicyclers riding in a single file line.
People in a race.
Riding in a single file line doesn't necessarily imply a race is taking place
exists e1 s1 x1 x2 x3 x4.(a_topic(x1) & in(e1,x3) & n_line(x3) & of(x3,x4) & n_file(x4) & a_single(s1) & Theme(s1,x3) & Actor(e1,x2) & v_ride(e1) & (x1 = x2) & n_bicycler(x1))
exists x1 x2.(a_topic(x1) & in(x1,x2) & n_race(x2) & n_people(x1))