After the cake had been divided into 20parts,the host took them before the guest.这里为什么用had been
问题描述：
After the cake had been divided into 20parts,the host took them before the guest.这里为什么用had been
答
过去完成时 表示过去的过去 主持人took这个动作是过去 那么切蛋糕这个动作是 过去的过去h好吧