The beginning of a cycling race passes by the crowd.
a race is passing
The phrase "a race is passing" is using the passive voice to restate the phrase "a race passes."
exists x1 x2 x3 x4 x5.(n_crowd(x5) & n_beginning(x1) & a_topic(x1) & by(x1,x5) & of(x1,x2) & n_pass(x2) & of(x2,x4) & n_race(x4) & of(x2,x3) & n_cycling(x3))
exists e1 x1.(Actor(e1,x1) & v_pass(e1) & n_race(x1))