Possibly three months."
( ( ( Possibly ( three months ) ) . ) '' )
(ROOT (S (VP (VB Possibly) (NP (CD three) (NNS months))) (. .) ('' '')))
It could be two months. 
( It ( ( could ( be ( two months ) ) ) . ) )
(ROOT (S (NP (PRP It)) (VP (MD could) (VP (VB be) (NP (CD two) (NNS months)))) (. .)))