过去完成时的被动语态有以下三种形式：
(1)肯定结构：主语+ had been done +其他成分
(2)否定结构：主语+ had not been done +其他成分
(3)疑问句结构：had +主语+ been done +其他成分;
疑问词+ had +主语+ been done +其他成分
温馨提示：
