but boulders Of the boy was teaching really .
(ROOT_0 (S_0 (ATS_3 (ATS_1 (CC_0 but) (NP_1 (NP_6 (NNS_1 boulders)) (PP_0 (IN_1 Of) (NP_5 (DT_0 the) (NN_2 boy))))) (VP_3 (VBD_1 was) (VP_2 (VBG_0 teaching) (ADVP_0 (RB_0 really))))) (DOT_0 .)))