be low , very low , very very low , 
(ROOT (S (VP (VB be) (ADJP (ADJP (JJ low)) (, ,) (ADJP (RB very) (JJ low)) (, ,) (ADJP (RB very) (RB very) (JJ low)))) (, ,)))
(ROOT (S (VP (VB ) (ADJP (ADJP (JJ )) (, ) (ADJP (RB ) (JJ )) (, ) (ADJP (RB ) (RB ) (JJ )))) (, )))