Teens dressed as Native Americans sit in the park with their school bags on the ground.
A group of boys are celebrating Native American culture.
To sit does not imply to celebrate and not all tens are boys.
exists e1 p1 s1 x1 x2 x3 x4 x5 x6.(n_ground(x6) & n_bag(x4) & of(x4,x5) & n_school(x5) & of(x4,x3) & n_thing(x3) & n_park(x3) & ne_nam_americans(x2) & a_native(s1) & Theme(s1,x2) & exists e2.(on(e2,x6) & in(e2,x3) & with(x3,x4) & Actor(e2,x2) & v_sit(e2)) & as(e1,p1) & Actor(e1,x1) & v_dress(e1) & n_teens(x1))
exists e1 s1 s2 x1 x2 x3.(Theme(e1,x3) & Actor(e1,x1) & v_celebrate(e1) & n_culture(x3) & a_american(s2) & Theme(s2,x3) & a_native(s1) & Theme(s1,x3) & of(x1,x2) & n_boy(x2) & n_group(x1))