(IP 
  (ADVP 
    (AD 因此))
                    
  (NP-TMP 
    (NP 
      (NT 六四))
                    
    (QP 
      (OD 十))
                    
    (NP 
      (NN 周年)))
                    
  (PU ，)
                    
  (IP-ADV 
    (NP-SBJ 
      (NN 大陆))
                    
    (VP 
      (ADVP 
        (CS 虽))
                    
      (PP-PRP 
        (P 因)
                    
        (IP 
          (NP-SBJ 
            (NN 官方))
                    
          (VP 
            (ADVP 
              (AD 刻意))
                    
            (VP 
              (VV 防范)))))
                    
      (PU ，)
                    
      (ADVP 
        (AD 难))
                    
      (VP 
        (VE 有)
                    
        (IP-OBJ 
          (NP-SBJ 
            (ADJP 
              (JJ 实质))
                    
            (NP 
              (NN 活动)))
                    
          (VP 
            (VV 冲击)
                    
            (NP-OBJ 
              (NN 当局)))))))
                    
  (PU ，)
                    
  (ADVP 
    (AD 但))
                    
  (LCP-LOC 
    (NP 
      (CP 
        (WHNP-1 
          (-NONE- *OP*))
                    
        (CP 
          (IP 
            (NP-SBJ 
              (-NONE- *T*-1))
                    
            (VP 
              (LCP-TMP 
                (NP 
                  (NT 五月))
                    
                (LC 初))
                    
              (PP-LOC 
                (P 在)
                    
                (NP-PN 
                  (NR 北京)
                    
                  (NN 大学)))
                    
              (VP 
                (VV 举行))))
                    
          (DEC 的)))
                    
      (NP-TTL 
        (PU 「)
                    
        (NP 
          (NT 五四))
                    
        (CC 与)
                    
        (NP 
          (NP 
            (QP 
              (OD 二十))
                    
            (NP 
              (NN 世纪)))
                    
          (NP-PN 
            (NR 中国)))
                    
        (PU 」))
                    
      (NP 
        (NN 研讨会)))
                    
    (LC 上))
                    
  (PU ，)
                    
  (NP-SBJ 
    (NN 参与者))
                    
  (VP 
    (VP 
      (ADVP 
        (AD 很))
                    
      (VP 
        (VA 难)
                    
        (IP-OBJ 
          (NP-SBJ 
            (-NONE- *PRO*))
                    
          (VP 
            (ADVP 
              (AD 不))
                    
            (VP 
              (VV 借题发挥))))))
                    
    (PU ，)
                    
    (VP 
      (ADVP 
        (AD 总是))
                    
      (VP 
        (VRD 
          (VV 碰触)
                    
          (VV 到))
                    
        (NP-OBJ 
          (NP 
            (NT 六四))
                    
          (DNP 
            (NP 
              (NN 背後))
                    
            (DEG 的))
                    
          (NP-APP 
            (NN 民主)
                    
            (PU 、)
                    
            (NN 人权)
                    
            (PU 、)
                    
            (NN 自由)
                    
            (ETC 等))
                    
          (CP 
            (WHNP-2 
              (-NONE- *OP*))
                    
            (CP 
              (IP 
                (NP-SBJ 
                  (-NONE- *T*-2))
                    
                (VP 
                  (NP-TMP 
                    (NN 当下))
                    
                  (VP 
                    (ADVP 
                      (AD 最))
                    
                    (VP 
                      (VA 敏感)))))
                    
              (DEC 的)))
                    
          (NP 
            (NN 话题)))))
                    
    (PU ，)
                    
    (VP 
      (VV 让)
                    
      (NP-OBJ 
        (NT 五四)
                    
        (NN 研讨会))
                    
      (IP 
        (NP-SBJ 
          (-NONE- *PRO*))
                    
        (VP 
          (VV 充满)
                    
          (AS 了)
                    
          (NP-OBJ 
            (CP-APP 
              (IP 
                (PU 「)
                    
                (NP-SBJ 
                  (DNP 
                    (ADJP 
                      (JJ 所有))
                    
                    (DEG 的))
                    
                  (NP 
                    (NN 历史)))
                    
                (VP 
                  (ADVP 
                    (AD 都))
                    
                  (VP 
                    (VC 是)
                    
                    (NP-PRD 
                      (NN 当代史))))
                    
                (PU 」))
                    
              (DEC 的))
                    
            (NP 
              (NN 气氛))))))))
arg0: 
                    *PRO* 
                
argm: 
                    不