A boy in a black shirt has thrown a snowball that has left a trail of snow behind it in the air.
The boy is walking on a hiking trip
A boy cannot walk on a hiking trip while throwing snowballs.
exists e2 e1 s1 x1 x2 x3 x4 x5 x6 x7.(n_air(x7) & Theme(e2,x3) & Actor(e2,x1) & v_throw(e2) & in(e1,x7) & Theme(e1,x5) & Actor(e1,x4) & v_leave(e1) & behind(x5,x1) & n_thing(x1) & of(x5,x6) & n_snow(x6) & n_trail(x5) & (x3 = x4) & n_snowball(x3) & in(x1,x2) & n_shirt(x2) & a_black(s1) & Theme(s1,x2) & n_boy(x1))
exists e1 x1 x2 x3.(n_boy(x1) & on(e1,x2) & n_trip(x2) & of(x2,x3) & n_hiking(x3) & Actor(e1,x1) & v_walk(e1))