Um, I guess the time when I was four.
( Um ( , ( I ( ( guess ( ( the time ) ( when ( I ( was four ) ) ) ) ) . ) ) ) )
(ROOT (S (ADVP (RB Um)) (, ,) (NP (PRP I)) (VP (VBP guess) (NP (NP (DT the) (NN time)) (SBAR (WHADVP (WRB when)) (S (NP (PRP I)) (VP (VBD was) (NP (CD four))))))) (. .)))
Probably when I was four.
( Probably ( ( when ( I ( was four ) ) ) . ) )
(ROOT (FRAG (ADVP (RB Probably)) (SBAR (WHADVP (WRB when)) (S (NP (PRP I)) (VP (VBD was) (NP (CD four))))) (. .)))