`` they were Trailing a back hill .
(ROOT_0 (S_0 (ATS_3 (ATS_1 (TICK_0 ``) (NP_1 (PRP_1 they))) (VP_3 (VBD_1 were) (VP_2 (VBG_0 Trailing) (NP_2 (ATNP_1 (DT_0 a) (JJ_1 back)) (NN_1 hill))))) (DOT_0 .)))