that distance discovered when ahead cows , you <apostrophe>s .
(ROOT_0 (S_0 (ATS_3 (NP_1 (DT_1 that) (NN_2 distance)) (VP_4 (VBD_0 discovered) (SBAR_0 (WHADVP_0 (WRB_0 when)) (S_1 (ATS_1 (ATS_2 (ADVP_0 (RB_1 ahead) (NP_4 (NNS_1 cows))) (COMMA_0 ,)) (NP_0 (PRP_1 you))) (VP_3 (VBZ_0 <apostrophe>s)))))) (DOT_0 .)))