The surfer left in regional boulders , then .
(ROOT_0 (S_0 (ATS_3 (NP_1 (DT_1 The) (NN_2 surfer)) (VP_4 (VBD_2 left) (PP_0 (IN_1 in) (NP_6 (ATNP_0 (NP_4 (JJ_1 regional) (NNS_1 boulders)) (COMMA_0 ,)) (ADVP_0 (RB_0 then)))))) (DOT_0 .)))