( Observation ( ( is ( ( the ( commonest form ) ) ( of ( ( ( ( learning , ) ( dominating ( ( the ( formative stages ) ) ( of childhood ) ) ) ) and ) ( remaining ( active ( throughout ( adult life ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Observation)) (VP (VBZ is) (NP (NP (DT the) (JJ commonest) (NN form)) (PP (IN of) (S (VP (VP (VBG learning)) (, ,) (VP (VBG dominating) (NP (NP (DT the) (JJ formative) (NNS stages)) (PP (IN of) (NP (NN childhood))))) (CC and) (VP (VBG remaining) (ADJP (JJ active) (PP (IN throughout) (NP (JJ adult) (NN life)))))))))) (. .)))
Observation is the commonest form of learning, dominating the formative stages of childhood and remaining active throughout adult life.
(ROOT (S (NP (NNP Childhood)) (VP (VBZ is) (ADJP (ADJP (RB typically) (JJR easier)) (PP (IN for) (S (VP (VBG learning) (NP (JJ multiple) (NNS languages))))))) (. .)))