(IP 
  (NP-PN-SBJ 
    (NR 香港))
                    
  (VP 
    (ADVP 
      (AD 也))
                    
    (VP 
      (VC 是)
                    
      (NP-PRD 
        (NP-PN 
          (NR 武汉))
                    
        (CP 
          (WHNP-1 
            (-NONE- *OP*))
                    
          (CP 
            (IP 
              (NP-SBJ 
                (-NONE- *T*-1))
                    
              (VP 
                (ADVP 
                  (AD 最))
                    
                (VP 
                  (VA 主要))))
                    
            (DEC 的)))
                    
        (NP 
          (NN 贸易)
                    
          (NN 伙伴))))))
arg0: 
                    *T*-1 
                
argm: 
                    最