While pretending, Vygotsky explained, children repeatedly face confiicts between the rules of the make-believe situation and what they would do if they could act impulsively, and they usually decide in favor of the rules.
( ( ( ( ( ( While pretending ) ( , ( Vygotsky ( ( explained , ) ( ( ( children ( repeatedly ( face ( confiicts ( between ( ( the rules ) ( of ( the ( make-believe situation ) ) ) ) ) ) ) ) ) and ) ( what ( they ( would ( do ( if ( they ( could ( act impulsively ) ) ) ) ) ) ) ) ) ) ) ) ) , ) and ) ( they ( usually ( decide ( in ( favor ( of ( the rules ) ) ) ) ) ) ) ) . )
(ROOT (S (S (SBAR (IN While) (FRAG (ADJP (JJ pretending)))) (, ,) (NP (NNP Vygotsky)) (VP (VBD explained) (, ,) (SBAR (SBAR (S (NP (NNS children)) (ADVP (RB repeatedly)) (VP (VBP face) (NP (NP (NNS confiicts)) (PP (IN between) (NP (NP (DT the) (NNS rules)) (PP (IN of) (NP (DT the) (JJ make-believe) (NN situation))))))))) (CC and) (SBAR (WHNP (WP what)) (S (NP (PRP they)) (VP (MD would) (VP (VB do) (SBAR (IN if) (S (NP (PRP they)) (VP (MD could) (VP (VB act) (ADVP (RB impulsively))))))))))))) (, ,) (CC and) (S (NP (PRP they)) (ADVP (RB usually)) (VP (VBP decide) (PP (IN in) (NP (NP (NN favor)) (PP (IN of) (NP (DT the) (NNS rules))))))) (. .)))
Children have to make choices when pretending if they will act out of impulse or follow the rules of the make-believe situation, and they usually choose to follow the rules. 
( ( ( ( ( Children ( have ( to ( ( make choices ) ( when ( pretending ( if ( they ( will ( ( ( ( act out ) ( of impulse ) ) or ) ( follow ( ( the rules ) ( of ( the ( make-believe situation ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) , ) and ) ( they ( usually ( choose ( to ( follow ( the rules ) ) ) ) ) ) ) . )
(ROOT (S (S (NP (NNP Children)) (VP (VBP have) (S (VP (TO to) (VP (VB make) (NP (NNS choices)) (SBAR (WHADVP (WRB when)) (S (VP (VBG pretending) (SBAR (IN if) (S (NP (PRP they)) (VP (MD will) (VP (VP (VB act) (PRT (RP out)) (PP (IN of) (NP (NN impulse)))) (CC or) (VP (VB follow) (NP (NP (DT the) (NNS rules)) (PP (IN of) (NP (DT the) (JJ make-believe) (NN situation))))))))))))))))) (, ,) (CC and) (S (NP (PRP they)) (ADVP (RB usually)) (VP (VBP choose) (S (VP (TO to) (VP (VB follow) (NP (DT the) (NNS rules))))))) (. .)))