They <apostrophe>m Plus sounded mountains .
(ROOT_0 (S_0 (ATS_3 (NP_1 (PRP_0 They)) (VP_4 (ATVP_1 (VP_5 (VBP_0 <apostrophe>m)) (CC_0 Plus)) (VP_5 (VBD_1 sounded) (NP_3 (NNS_1 mountains))))) (DOT_0 .)))