A person in a white shirt skateboarding off a rail.
A person performing a trick on a skateboard in front of his friends
Just because there is a person on a skateboard, it doesn't mean that he is in front of his friends.
exists e1 s1 s2 x1 x2 x3 x4.(a_topic(x1) & in(x1,x2) & a_off(s2) & Manner(e1,s2) & Theme(e1,x4) & Actor(e1,x3) & v_skateboard(e1) & n_rail(x4) & (x2 = x3) & n_shirt(x2) & a_white(s1) & Theme(s1,x2) & n_person(x1))
exists e1 x1 x2 x3 x4 x5 x6.(a_topic(x1) & in(e1,x5) & of(x5,x6) & n_friend(x6) & of(x6,x1) & n_male(x1) & n_front(x5) & on(e1,x4) & n_skateboard(x4) & Theme(e1,x3) & Actor(e1,x2) & v_perform(e1) & n_trick(x3) & (x1 = x2) & n_person(x1))