Boys and men, mostly all wearing helmets, hang on to two separate cars while they ride skateboards.
Boys and men are doing risky skateboarding.
Boys ride skateboards must mean they are risky skateboarding.
exists e1 p1 s1 s2 x1 x2 x3 x4 x5 x6 x7.(rel(e1,x5) & subset_of(x7,x5) & n_man(x7) & subset_of(x6,x5) & n_boy(x6) & exists e2 x8.(Theme(e2,x8) & Actor(e2,x1) & v_ride(e2) & n_skateboard(x8)) & n_thing(x1) & while(e1,p1) & Theme(e1,x2) & Actor(e1,x1) & v_wear(e1) & rel(x2,x3) & on(x3,x4) & n_car(x4) & a_separate(s2) & Theme(s2,x4) & card_eq_2(x4) & r_to(x4) & n_hang(x3) & n_helmet(x2) & n_all(x1) & a_mostly(s1) & Theme(s1,x1))
exists e1 s1 x1 x2 x3 x4.(Theme(e1,x4) & Actor(e1,x1) & v_do(e1) & n_skateboarding(x4) & a_risky(s1) & Theme(s1,x4) & subset_of(x3,x1) & n_man(x3) & subset_of(x2,x1) & n_boy(x2))