Two people wearing racing uniforms are riding racing motorcycles.
Two people are driving their vehicles.
A motorcycle is a vehicle, and riding motorcycles is the same thing as driving them.
exists e2 e1 x1 x2 x3 x4 x5 x6.(Theme(e2,x5) & Actor(e2,x1) & v_ride(e2) & n_motorcycle(x5) & of(x5,x6) & n_racing(x6) & Theme(e1,x3) & Actor(e1,x2) & v_wear(e1) & n_uniform(x3) & of(x3,x4) & n_racing(x4) & (x1 = x2) & n_people(x1) & card_eq_2(x1))
exists e1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_drive(e1) & n_vehicle(x2) & of(x2,x1) & n_thing(x1) & n_people(x1) & card_eq_2(x1))