由于假期积压了大量订单，仓库工作人员正在加班处理。

The warehouse staff are working overtime to handle the ___backlogged orders from the holiday season.

由于系统升级，客服回复可能被积压几天。

Customer service responses may be ___backlogged for a few days due to system updates.

由于网络问题，应用程序自动备份了未发送的消息。

The app automatically ___backed up the unsent messages due to network issues.