Bikers race through a forest.
Bikers race through a busy street.
A forest is not a busy street.
exists x1 x2 x3.(a_topic(x1) & through(x1,x3) & n_forest(x3) & n_race(x1) & of(x1,x2) & n_biker(x2))
exists s1 x1 x2 x3.(a_topic(x1) & through(x1,x3) & n_street(x3) & a_busy(s1) & Theme(s1,x3) & n_race(x1) & of(x1,x2) & n_biker(x2))