to keep keep anything to the waist-high surfer of n<apostrophe>t higher , you is .
(ROOT_0 (S_0 (ATS_3 (ATS_1 (ATS_0 (S_2 (VP_0 (TO_0 to) (VP_1 (VB_0 keep) (VP_2 (ATVP_4 (VB_0 keep) (NP_2 (NN_3 anything))) (PP_2 (TO_0 to) (NP_3 (NP_6 (ATNP_1 (DT_0 the) (JJ_1 waist-high)) (NN_1 surfer)) (PP_0 (IN_1 of) (NP_6 (RB_1 n<apostrophe>t) (JJR_0 higher))))))))) (COMMA_0 ,)) (NP_0 (PRP_1 you))) (VP_3 (VBZ_0 is))) (DOT_0 .)))