A man in a red uniform makes a jump in a dirt bike race.
The man is riding by himself.
One cannot be by themselves and in a race because race implies that you aren't alone.
exists e1 s1 x1 x2 x3 x4 x5 x6.(Theme(e1,x3) & Actor(e1,x1) & v_make(e1) & in(x3,x4) & n_race(x4) & of(x4,x6) & n_bike(x6) & of(x4,x5) & n_dirt(x5) & n_jump(x3) & in(x1,x2) & n_uniform(x2) & a_red(s1) & Theme(s1,x2) & n_man(x1))
exists e1 x1.(n_male(x1) & n_man(x1) & by(e1,x1) & Actor(e1,x1) & v_ride(e1))