I'm confused.
( I ( ( 'm confused ) . ) )
(ROOT (S (NP (PRP I)) (VP (VBP 'm) (ADJP (VBN confused))) (. .)))
I understand it perfectly.
( I ( ( ( understand it ) perfectly ) . ) )
(ROOT (S (NP (PRP I)) (VP (VBP understand) (NP (PRP it)) (ADVP (RB perfectly))) (. .)))