( (IP (IP (ADVP (AD 此后))
(PU ，)
(LCP-SBJ (NP (NN 电车)
(NN 轨道))
(LC 上))
(VP (VV 挤满)
(AS 了)
(NP-OBJ (NN 电车))))
(PU ，)
(IP (NP-SBJ (DP (DT 该))
(NP (NN 系统)))
(VP (VV 变得)
(IP-OBJ (NP-SBJ (-NONE- *PRO*))
(VP (VA 拥挤不堪)))))
(PU 。)))
ARG0: *PRO*
REL: 拥挤不堪