Young boy encounters other children, also riding bikes.
Children prepare for a bicycle race.
A boy encounters other children, also riding bikes doesn't mean that they are preparing for a bicycle race.
exists e1 e2 s1 s2 x1 x2 x3 x4.(n_child(x3) & for(e1,e2) & a_also(s2) & Manner(e2,s2) & Theme(e2,x4) & Actor(e2,x1) & v_ride(e2) & n_bike(x4) & Theme(e1,x2) & Actor(e1,x1) & v_encounter(e1) & -(x2 = x3) & n_child(x2) & n_boy(x1) & a_young(s1) & Theme(s1,x1))
exists e1 x1 x2 x3.(for(e1,x2) & n_race(x2) & of(x2,x3) & n_bicycle(x3) & Actor(e1,x1) & v_prepare(e1) & n_child(x1))