call to order:
1、宣布开（会）.例句：The press sacretary strode into the room and called the meeting to order.新闻秘书大步走进房间,宣布开会.
2、请……安静,请……遵守秩序.例句：The teacher called the class to order.教师要班上学生安静下来上课.
这句话的意思：会议宣布开始.