A fitness class with the attendees riding stationary bikes.
A fitness class works on bikes.
"Works on bikes" is a rephrasing of "riding stationary bikes.
exists e1 s1 x1 x2 x3 x4 x5.(n_attendee(x3) & a_topic(x1) & with(x1,x3) & Theme(e1,x5) & Actor(e1,x4) & v_ride(e1) & n_bike(x5) & a_stationary(s1) & Theme(s1,x5) & (x3 = x4) & n_class(x1) & of(x1,x2) & n_fitness(x2))
exists e1 x1 x2 x3.(on(e1,x3) & n_bike(x3) & Actor(e1,x1) & v_work(e1) & n_class(x1) & of(x1,x2) & n_fitness(x2))