Poirot answered them categorically, almost mechanically. 
( ( ( ( Poirot ( ( answered them ) categorically ) ) , ) ( almost mechanically ) ) . )
(ROOT (S (S (NP (NNP Poirot)) (VP (VBD answered) (NP (PRP them)) (ADVP (RB categorically)))) (, ,) (FRAG (ADJP (RB almost) (RB mechanically))) (. .)))
Poirot did not bother to answer them at all.
( Poirot ( ( ( did not ) ( bother ( to ( ( answer them ) ( at all ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Poirot)) (VP (VBD did) (RB not) (VP (VB bother) (S (VP (TO to) (VP (VB answer) (NP (PRP them)) (ADVP (IN at) (DT all))))))) (. .)))