Oh yes, yes they did.
( Oh ( yes ( , ( ( yes they ) ( did . ) ) ) ) )
(ROOT (S (INTJ (UH Oh)) (INTJ (UH yes)) (, ,) (NP (RB yes) (PRP they)) (VP (VBD did)) (. .)))
Yes they did offer free books.
( Yes ( they ( ( did ( offer ( free books ) ) ) . ) ) )
(ROOT (S (ADVP (RB Yes)) (NP (PRP they)) (VP (VBD did) (VP (VB offer) (NP (JJ free) (NNS books)))) (. .)))