It is a good idea to make a backup copy and then upgrade the copy before upgrading your production version.

在升级产品版本之前，先做一个复制的备份之后再升级复制，是一个明智的做法。

youdao

A transient variable enables the application to keep a copy in local memory, but rebuilds the object if using the backup copy.

临时变量允许应用程序在本地内存中保留副本，但可以在使用备份副本的情况下重新构建对象。

youdao

If you don't have a backup copy of the corrupt document readily available, make a copy of the corrupted file right away and store it on removable media.

如果你没有损坏文档的可读备份版本，需马上复制一份损坏文档的备份到可移动介质上。

youdao

You really need that because if you have only one copy of something, you don't have a backup; so, you can store the one copy separately.

你真的很需要这项发明,因为要是你只有一份的话，你就没有备份;,这样的话，你就可以将副本单独留存。

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Chances, are, however, you keep a backup copy of your operating system on an optical disc in the desk drawer, just in case.

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The goal, says Real Networks Vice President Jeff Chasen, is to do away with space-consuming discs and let users create a backup copy of their video collection.

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So, periodically, whenever network traffic permits, the endpoint and the cloud should have a handshake, during which the endpoint updates the cloud with a backup copy of any files unique to that endpoint.

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