Two runners, one in a red shirt and one in a black shirt, race in front of two men on a motorcycle.
Two runners are racing in front of men on motorcycles.
Two runners of red shirt and black shirt  are racing in front of men on motorcycles.
exists s1 s2 x1 x2 x3 x4 x5 x6 x7 x8 x9 x10.(a_topic(x1) & rel(x1,x2) & subset_of(x5,x2) & rel(x5,x7) & in(x7,x8) & of(x8,x9) & on(x9,x10) & n_motorcycle(x10) & n_man(x9) & card_eq_2(x9) & n_front(x8) & n_race(x7) & in(x5,x6) & n_shirt(x6) & a_black(s2) & Theme(s2,x6) & n_thing(x5) & card_eq_1(x5) & subset_of(x3,x2) & in(x3,x4) & n_shirt(x4) & a_red(s1) & Theme(s1,x4) & n_thing(x3) & card_eq_1(x3) & n_runner(x1) & card_eq_2(x1))
exists e1 x1 x2 x3 x4.(in(e1,x2) & of(x2,x3) & on(x3,x4) & n_motorcycle(x4) & n_man(x3) & n_front(x2) & Actor(e1,x1) & v_race(e1) & n_runner(x1) & card_eq_2(x1))