A boy dressed in all black sits on his bike.
Boy on a bike
Both sentences state the boy is on his bike.
exists e2 e1 x1 x2 x3.(on(e2,x3) & n_bike(x3) & of(x3,x1) & n_male(x1) & Actor(e2,x1) & v_sit(e2) & all x4.(n_black(x4) -> in(e1,x4)) & Theme(e1,x2) & v_dress(e1) & (x1 = x2) & n_boy(x1))
exists s1 x1.(ne_nam_boy(s1) & a_topic(s1) & on(s1,x1) & n_bike(x1))