Make-believe play, Vygotsky asserted, helps preschoolers conquer these impulses by granting the child repeated practice  in acting independently of what he sees. 
( ( Make-believe play ) ( ( , ( Vygotsky ( asserted , ) ) ) ( ( helps ( preschoolers ( ( conquer ( these impulses ) ) ( by ( ( granting ( the child ) ) ( ( repeated practice ) ( in ( ( acting independently ) ( of ( what ( he sees ) ) ) ) ) ) ) ) ) ) ) . ) ) )
(ROOT (S (NP (JJ Make-believe) (NN play)) (PRN (, ,) (NP (NNP Vygotsky)) (VP (VBD asserted)) (, ,)) (VP (VBZ helps) (S (NP (NNS preschoolers)) (VP (VB conquer) (NP (DT these) (NNS impulses)) (PP (IN by) (S (VP (VBG granting) (NP (DT the) (NN child)) (NP (NP (VBN repeated) (NN practice)) (PP (IN in) (S (VP (VBG acting) (ADVP (RB independently)) (PP (IN of) (SBAR (WHNP (WP what)) (S (NP (PRP he)) (VP (VBZ sees))))))))))))))) (. .)))
Children can't participate in make-believe plays.
( Children ( ( ( ca n't ) ( participate ( in ( make-believe plays ) ) ) ) . ) )
(ROOT (S (NP (NNP Children)) (VP (MD ca) (RB n't) (VP (VB participate) (PP (IN in) (NP (JJ make-believe) (NNS plays))))) (. .)))