I <apostrophe>s his sure surfers heard n<apostrophe>t unmistakably .
(ROOT_0 (S_0 (ATS_3 (NP_1 (PRP_0 I)) (VP_4 (VBZ_0 <apostrophe>s) (S_1 (NP_0 (ATNP_0 (PRPDOLLAR_0 his) (JJ_0 sure)) (NNS_0 surfers)) (VP_5 (ATVP_4 (VBD_0 heard) (RB_1 n<apostrophe>t)) (ADVP_0 (RB_0 unmistakably)))))) (DOT_0 .)))