Two people in racing clothes and helmets are riding motorcycles.
Two people are wearing black helmets.
Helmets are not all black.
exists e1 e2 x1 x2 x3 x4 x5 x6.(Theme(e2,x6) & Actor(e2,x1) & v_ride(e2) & n_motorcycle(x6) & Theme(e1,x3) & Actor(e1,x2) & v_race(e1) & subset_of(x5,x3) & n_helmet(x5) & subset_of(x4,x3) & n_clothes(x4) & (x1 = x2) & n_people(x1) & card_eq_2(x1))
exists e1 s1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_wear(e1) & n_helmet(x2) & a_black(s1) & Theme(s1,x2) & n_people(x1) & card_eq_2(x1))