them should stand doing by an grass , flats .
(ROOT_0 (S_0 (ATS_3 (NP_1 (PRP_0 them)) (VP_4 (MD_0 should) (VP_1 (VB_0 stand) (VP_2 (VBG_0 doing) (PP_2 (IN_0 by) (NP_3 (ATNP_0 (NP_0 (DT_0 an) (NN_2 grass)) (COMMA_0 ,)) (NNS_0 flats))))))) (DOT_0 .)))