digit back-up

例句：

1. 1. We need to ensure that all important data is backed up regularly.
   我们需要确保所有重要数据定期备份。
2. 2. The server's SSD has a built-in digital back-up system.
   服务器的固态硬盘内置了数字备份系统。
3. 3. To prevent data loss, we should always have a digital back-up of our files.
   为了防止数据丢失，我们应该总是对我们的文件进行数字备份。