that could have been much better 
(ROOT (S (NP (DT that)) (VP (MD could) (VP (VB have) (VP (VBN been) (ADJP (RB much) (JJR better)))))))
(ROOT (S (NP (DT )) (VP (MD ) (VP (VB ) (VP (VBN ) (ADJP (RB ) (JJR )))))))