These two accounts are commonly combined in discussing the Social Security program.
( ( These ( two accounts ) ) ( ( ( are commonly ) ( combined ( in ( discussing ( the ( Social ( Security program ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT These) (CD two) (NNS accounts)) (VP (VBP are) (ADVP (RB commonly)) (VP (VBN combined) (PP (IN in) (S (VP (VBG discussing) (NP (DT the) (NNP Social) (NNP Security) (NN program))))))) (. .)))
The Social Security program involves only one of the accounts.
( ( The ( Social ( Security program ) ) ) ( ( involves ( ( only one ) ( of ( the accounts ) ) ) ) . ) )
(ROOT (S (NP (DT The) (NNP Social) (NNP Security) (NN program)) (VP (VBZ involves) (NP (NP (QP (RB only) (CD one))) (PP (IN of) (NP (DT the) (NNS accounts))))) (. .)))