The last 12 years of his life are a blank.
( ( ( The ( last ( 12 years ) ) ) ( of ( his life ) ) ) ( ( are ( a blank ) ) . ) )
(ROOT (S (NP (NP (DT The) (JJ last) (CD 12) (NNS years)) (PP (IN of) (NP (PRP$ his) (NN life)))) (VP (VBP are) (NP (DT a) (JJ blank))) (. .)))
He can't remember the last 12 years of his life
( He ( ( ca n't ) ( remember ( ( the ( last ( 12 years ) ) ) ( of ( his life ) ) ) ) ) )
(ROOT (S (NP (PRP He)) (VP (MD ca) (RB n't) (VP (VB remember) (NP (NP (DT the) (JJ last) (CD 12) (NNS years)) (PP (IN of) (NP (PRP$ his) (NN life))))))))