Numerous bicyclists riding across a bridge.
The bicyclists wait to start their ride.
Waiting to start your ride  is contradictory with riding.
exists e1 s1 x1 x2 x3.(a_topic(x1) & across(e1,x3) & n_bridge(x3) & Actor(e1,x2) & v_ride(e1) & (x1 = x2) & n_bicyclist(x1) & a_numerous(s1) & Theme(s1,x1))
exists e1 p1 x1 x2.(n_ride(x2) & of(x2,x1) & n_thing(x1) & n_bicyclist(x1) & Topic(e1,p1) & Actor(e1,x1) & v_wait(e1) & exists e2.(Theme(e2,x2) & Actor(e2,x1) & v_start(e2)))