They help down but discovered the mountains .
(ROOT_0 (S_0 (ATS_3 (NP_1 (PRP_0 They)) (VP_4 (ATVP_1 (VP_5 (VB_0 help) (PRT_0 (RP_0 down))) (CC_0 but)) (VP_5 (VBD_0 discovered) (NP_6 (DT_0 the) (NNS_1 mountains))))) (DOT_0 .)))