low , very low , very very low 
(ROOT (ADJP (ADJP (JJ low)) (, ,) (ADJP (RB very) (JJ low)) (, ,) (ADJP (RB very) (RB very) (JJ low))))
(ROOT (ADJP (ADJP (JJ )) (, ) (ADJP (RB ) (JJ )) (, ) (ADJP (RB ) (RB ) (JJ ))))