Skateboarding grinding in a bootleg skate park.
A skateboarder is in a park and is happy.
The skateboarder in this sentence could be in any kind of park and not necessarily a skate park and just because they are at a park doesn't mean they are happy.
exists e1 x1 x2 x3 x4.(in(e1,x2) & n_park(x2) & of(x2,x4) & n_skate(x4) & of(x2,x3) & n_bootleg(x3) & Actor(e1,x1) & v_grind(e1) & n_skateboard(x1))
exists p1 s1 x1 x2.(Theme(s1,x2) & a_happy(s1) & n_skateboarder(x2) & exists x3.(in(x1,x3) & n_park(x3)) & n_skateboarder(x1))