(IP 
  (NP-SBJ 
    (QP 
      (CD 许多))
                    
    (NP 
      (NN 人)))
                    
  (VP 
    (VP 
      (VV 会)
                    
      (VP 
        (PP-PRP 
          (P 因为)
                    
          (IP 
            (NP-SBJ 
              (-NONE- *PRO*))
                    
            (VP 
              (VV 一时兴起))))
                    
        (VP 
          (VV 加入)
                    
          (NP-OBJ 
            (NN 健身)
                    
            (NN 中心)))))
                    
    (PU ，)
                    
    (VP 
      (ADVP 
        (AD 但))
                    
      (ADVP 
        (AD 往往))
                    
      (ADVP 
        (AD 也))
                    
      (ADVP 
        (AD 容易))
                    
      (VP 
        (VV 半途而废)))))
arg0: 
                    许多 人 
                
argm: 
                    容易 
                
argm: 
                    也 
                
argm: 
                    往往 
                
argm: 
                    但