(NP-SBJ 
  (PN 他们))
                    
(VP 
  (VP 
    (VP 
      (PP-DIR 
        (P 向)
                    
        (LCP 
          (NP 
            (NN 海))
                    
          (LC 中)))
                    
      (VP 
        (VV 抛洒)
                    
        (NP-OBJ 
          (NN 玫瑰花))))
arg0: 
                    他们          
                
argm: 
                    向 海 中          
                
arg1: 
                    玫瑰花