 

        

2019-10-24 13:14
  104
  0

                                                     
     1.                                              
     2 .      3            ①    ② 6         ③                  ④     
     3.                                            15      
     4.               1-2  
     5.               40        3          20     
     6.                                         



 



  
     
     