in in trips , Bolivian fixed why of a gravel .
(ROOT_0 (S_0 (ATS_3 (ATS_1 (ATS_2 (PP_2 (IN_0 in) (PP_2 (IN_0 in) (NP_3 (NNS_1 trips)))) (COMMA_0 ,)) (NP_0 (NNP_0 Bolivian))) (VP_3 (VBD_1 fixed) (VP_2 (VBN_0 why) (PP_0 (IN_1 of) (NP_5 (DT_0 a) (NN_2 gravel)))))) (DOT_0 .)))