back the boy had mattered on remains group .
(ROOT_0 (S_0 (ATS_3 (ATS_1 (RB_1 back) (NP_5 (DT_0 the) (NN_2 boy))) (VP_3 (VBD_1 had) (VP_2 (VBN_0 mattered) (PP_2 (IN_0 on) (NP_3 (NP_4 (NNS_1 remains)) (NN_2 group)))))) (DOT_0 .)))