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(ROOT_0 (S_0 (ATS_3 (NP_1 (PRP_0 He)) (VP_4 (VBZ_0 <apostrophe>s) (S_1 (NP_0 (PRP_1 he)) (VP_5 (VBP_0 refer) (SBAR_0 (WHNP_0 (WP_0 what)) (S_2 (TO_0 to))))))) (DOT_0 .)))