The kid is showing off on his skateboard in front of a large crowd.
The kid is sitting on his skateboard in front of a large crowd.
While the kid could be showing off on his skateboard by sitting on it, the words showing off imply that he is riding the skateboard and perhaps doing tricks on it.
exists e1 s1 s2 x1 x2 x3 x4.(n_skateboard(x2) & of(x2,x1) & n_male(x1) & n_kid(x1) & a_off(s2) & Manner(e1,s2) & on(e1,x2) & in(x2,x3) & of(x3,x4) & n_crowd(x4) & a_large(s1) & Theme(s1,x4) & n_front(x3) & Actor(e1,x1) & v_show(e1))
exists e1 s1 x1 x2 x3 x4.(n_skateboard(x2) & of(x2,x1) & n_male(x1) & n_kid(x1) & in(e1,x3) & of(x3,x4) & n_crowd(x4) & a_large(s1) & Theme(s1,x4) & n_front(x3) & on(e1,x2) & Actor(e1,x1) & v_sit(e1))