`` back car was doing doing . he fell off about class .
(ROOT_0 (S_0 (ATS_3 (ATS_1 (ATS_2 (ATS_3 (ATS_1 (ATS_2 (TICK_0 ``) (ADVP_0 (RB_0 back))) (NP_0 (NN_2 car))) (VP_3 (VBD_1 was) (VP_2 (VBG_0 doing) (S_2 (VBG_0 doing))))) (DOT_0 .)) (NP_0 (PRP_0 he))) (VP_3 (ATVP_3 (VBD_2 fell) (PRT_0 (RP_0 off))) (PP_0 (IN_1 about) (NP_5 (NN_3 class))))) (DOT_0 .)))