Definition: to make an extra copy of something that is held on your computer Level: B2
总是备份你下载的任何音乐，以防电脑崩溃。
Always ___back ___up any music you download in case your computer crashes.
你应该定期备份你的重要文件。
You should ___back ___up your important files regularly.
在删除之前别忘了备份它。
Don't forget to ___back it ___up before you delete it.
