 He grimaced at his own doubts.
( He ( ( grimaced ( at ( his ( own doubts ) ) ) ) . ) )
(ROOT (S (NP (PRP He)) (VP (VBD grimaced) (PP (IN at) (NP (PRP$ his) (JJ own) (NNS doubts)))) (. .)))
He felt bad for doubting her.
( He ( ( felt ( bad ( for ( doubting her ) ) ) ) . ) )
(ROOT (S (NP (PRP He)) (VP (VBD felt) (ADJP (JJ bad) (PP (IN for) (S (VP (VBG doubting) (NP (PRP her))))))) (. .)))