(IP (IP-CND (NP-SBJ (-NONE- *pro*))
(VP (ADVP (CS 一旦))
(VP (VV 揭穿)
(NP-OBJ (NN 谜底)))))
(PU ，)
(IP-SBJ (NP-SBJ (-NONE- *PRO*))
(VP (VV 要)
(VP (VV 模仿))))
(VP (ADVP (AD 并))
(ADVP (AD 不))
(VP (VA 困难))))
ARG0: *pro*
ARG1: 谜底
ARGM-ADV: 一旦
REL: 揭穿