grind that only the most hardhearted scrooge could fail to respond 
(ROOT (S (VP (VB grind) (SBAR (IN that) (S (NP (RB only) (DT the) (ADJP (RBS most) (JJ hardhearted)) (NN scrooge)) (VP (MD could) (VP (VB fail) (S (VP (TO to) (VP (VB respond)))))))))))
(ROOT (S (VP (VB ) (SBAR (IN ) (S (NP (RB ) (DT ) (ADJP (RBS ) (JJ )) (NN )) (VP (MD ) (VP (VB ) (S (VP (TO ) (VP (VB )))))))))))