(VP 
  (VV 解决)
                    
  (NP-OBJ-3 
    (CP 
      (WHNP-2 
        (-NONE- *OP*))
                    
      (CP 
        (IP 
          (NP-SBJ 
            (-NONE- *T*-2))
                    
          (VP 
            (ADVP 
              (AD 难以))
                    
            (VP 
              (VV 预料))))
                    
        (DEC 的)))
                    
    (NP 
      (NN 问题))))
arg1: 
                    *T*-2 
                
argm: 
                    难以