They could stop who an world did up .
(ROOT_0 (S_0 (ATS_3 (NP_1 (PRP_0 They)) (VP_4 (MD_0 could) (VP_1 (VB_0 stop) (SBAR_0 (WHNP_0 (WP_0 who)) (S_1 (NP_0 (DT_0 an) (NN_2 world)) (VP_5 (VBD_0 did) (PRT_0 (RP_0 up)))))))) (DOT_0 .)))