That was Robert Frost.
( That ( ( was ( Robert Frost ) ) . ) )
(ROOT (S (NP (DT That)) (VP (VBD was) (NP (NNP Robert) (NNP Frost))) (. .)))
That was definitely Robert Frost.
( That ( ( ( was definitely ) ( Robert Frost ) ) . ) )
(ROOT (S (NP (DT That)) (VP (VBD was) (ADVP (RB definitely)) (NP (NNP Robert) (NNP Frost))) (. .)))