Using it to bolster an argument is plainly a mistake.
( ( Using ( it ( to ( bolster ( an argument ) ) ) ) ) ( ( ( is plainly ) ( a mistake ) ) . ) )
(ROOT (S (S (VP (VBG Using) (S (NP (PRP it)) (VP (TO to) (VP (VB bolster) (NP (DT an) (NN argument))))))) (VP (VBZ is) (ADVP (RB plainly)) (NP (DT a) (NN mistake))) (. .)))
I should have done something more constructive than argue.
( I ( ( should ( have ( done ( something ( more ( constructive ( than argue ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (PRP I)) (VP (MD should) (VP (VB have) (VP (VBN done) (S (NP (NN something)) (ADJP (RBR more) (JJ constructive) (SBAR (IN than) (S (VP (VBP argue))))))))) (. .)))