兔几小兔几
xxx as backup例句你可以使用传统的暖气系统作为备用。You can use a conventional heating system as backup.
暖暖滴嗳
Backup; spare; reserve; standby; alternate 请问是备用什么呢? e.g., Most hospitals have backup generators in case of blackouts. It's best to always carry a spare tyre when driving long distances. I had to dip into my reserve funds when the business got into trouble.
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