The young man is skateboarding at a skate park.
A new skate park opened an a boy is skateboarding in it with his friends
Not all skate parks are a new skate park.  Skateboarding does not imply it is with his friends.
exists e1 s1 x1 x2 x3.(n_man(x1) & a_young(s1) & Theme(s1,x1) & at(e1,x2) & n_park(x2) & of(x2,x3) & n_skate(x3) & Actor(e1,x1) & v_skateboard(e1))
exists e1 e2 s1 x1 x2 x3 x4 x5.(in(e2,x1) & n_thing(x1) & with(e2,x5) & n_friend(x5) & of(x5,x1) & n_male(x1) & Actor(e2,x1) & v_skateboard(e2) & Theme(e1,x4) & Actor(e1,x3) & v_open(e1) & n_boy(x4) & (x1 = x3) & n_park(x1) & of(x1,x2) & n_skate(x2) & a_new(s1) & Theme(s1,x1))