appropriate sudden flats let This <apostrophe>s phrase lesson .
(ROOT_0 (S_0 (ATS_3 (NP_1 (ATNP_0 (JJ_0 appropriate) (JJ_1 sudden)) (NNS_0 flats)) (VP_4 (VBD_0 let) (SBAR_0 (S_1 (NP_0 (DT_1 This)) (VP_5 (VBZ_0 <apostrophe>s) (NP_2 (NN_2 phrase) (NN_3 lesson))))))) (DOT_0 .)))