a kingdom more mild than wild 
(ROOT (NP (NP (DT a) (NN kingdom)) (ADJP (ADJP (RBR more) (JJ mild)) (PP (IN than) (ADJP (JJ wild))))))
(ROOT (NP (NP (DT ) (NN )) (ADJP (ADJP (RBR ) (JJ )) (PP (IN ) (ADJP (JJ ))))))