They do who slithered been back by the morning .
(ROOT_0 (S_0 (ATS_3 (NP_1 (PRP_0 They)) (VP_4 (VBP_0 do) (SBAR_0 (WHNP_0 (WP_0 who)) (S_2 (VP_0 (VBD_2 slithered) (VP_2 (VBN_0 been) (PP_2 (ATPP_0 (ADVP_0 (RB_0 back)) (IN_2 by)) (NP_5 (DT_0 the) (NN_2 morning))))))))) (DOT_0 .)))