(IP 
  (NP-SBJ 
    (NN 菸楼))
                    
  (VP 
    (VC 是)
                    
    (NP-PRD 
      (CP 
        (WHNP-1 
          (-NONE- *OP*))
                    
        (CP 
          (IP 
            (NP-SBJ 
              (-NONE- *T*-1))
                    
            (VP 
              (VV 用来)
                    
              (IP-OBJ 
                (NP-SBJ 
                  (-NONE- *PRO*))
                    
                (VP 
                  (VP 
                    (VV 烤火))
                    
                  (VP 
                    (VV 熏)
                    
                    (NP-OBJ 
                      (NN 菸叶)))))))
                    
          (DEC 的))))))
arg0: 
                    *PRO*