Three children pose outdoors on a hike.
Children go on their first big hike.
the fact that the children are posing outdoors on a hike does not imply that they are on their first big hike.  They may have gone on hikes before, and the hike may not be a big hike.
exists e1 x1 x2 x3.(on(e1,x3) & n_hike(x3) & Theme(e1,x2) & Actor(e1,x1) & v_pose(e1) & n_outdoors(x2) & n_child(x1) & card_eq_3(x1))
exists e1 s1 s2 x1 x2.(on(e1,x2) & n_hike(x2) & a_big(s2) & Theme(s2,x2) & a_first(s1) & Theme(s1,x2) & of(x2,x1) & n_thing(x1) & Actor(e1,x1) & v_go(e1) & n_child(x1))