Children playing on rocks.
The children are playing with rare rocks unknowingly.
It is not necessary that the rocks are rare
exists e1 x1 x2 x3.(a_topic(x1) & on(e1,x3) & n_rock(x3) & Actor(e1,x2) & v_play(e1) & (x1 = x2) & n_child(x1))
exists e1 s1 s2 x1 x2.(n_child(x1) & a_unknowingly(s2) & Manner(e1,s2) & with(e1,x2) & n_rock(x2) & a_rare(s1) & Theme(s1,x2) & Actor(e1,x1) & v_play(e1))