(S (S (S (NP (BASENP (VBG Increasing) (NNS levels)) (PP (IN of) (BASENP (NN activity)))) (VP (VBD saw) (NP (BASENP (VBG decreasing) (NNS chances)) (PP (IN of) (BASENP (NN childhood) (NNS cancers)))))) (COMMA ,) (SBAR (WHADVP (WRB when)) (S (VP (VBN compared) (PP (IN against) (NP (BASENP (NNS children)) (SBAR (WHNP (WP who)) (S (VP (PP (IN during) (BASENP (PRPD their) (JJ first) (NN year))) (VP (VBD had) (NP (BASENP (DT no) (JJ regular) (JJ social) (NN activity)) (PP (IN outside) (BASENP (DT the) (NN home)))))))))))))) (PERIOD .))