North Polytechnic machinery and vehicle Institute held a youth exchange meeting onNorth Polytechnic machinery and vehicle Institute held a youth exchange meeting onNorth Polytechnic machinery and vehicle Institute held a youth exchange meeting on

　　North Polytechnic machinery and vehicle Institute held a youth exchange meeting onNorth Polytechnic machinery and vehicle Institute held a youth exchange meeting onNorth Polytechnic machinery and vehicle Institute held a youth exchange meeting on

　　North Polytechnic machinery and vehicle Institute held a youth exchange meeting onNorth Polytechnic machinery and vehicle Institute held a youth exchange meeting onNorth Polytechnic machinery and vehicle Institute held a youth exchange meeting on