The young girl happily plays in the tree.
The girl is angry.
A young girl is more specific than just a girl. The girl who is happy and plays in a tree is not the same as a girl who is angry. We do not know where this angry girl is either, she probably is not in a tree.
exists e1 s1 s2 x1 x2.(n_tree(x2) & n_girl(x1) & a_young(s1) & Theme(s1,x1) & a_happily(s2) & Manner(e1,s2) & in(e1,x2) & Actor(e1,x1) & v_play(e1))
exists s1 x1.(n_girl(x1) & Theme(s1,x1) & a_angry(s1))