That boy would stop to warily was .
(ROOT_0 (S_0 (ATS_3 (NP_1 (DT_1 That) (NN_2 boy)) (VP_4 (MD_0 would) (VP_1 (VB_0 stop) (S_2 (VP_0 (TO_0 to) (VP_1 (ADVP_0 (RB_0 warily)) (VBD_1 was))))))) (DOT_0 .)))