Once opened, this product should be kept refrigerated.

本产品开封后应冷藏。

《牛津词典》

Once opened, the XML file is mapped into tabular structure.

这个 XML 文件被打开后，就会被映射到表结构中。

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The malicious PPT files try to drop malware once opened. Here is a screenshot with the process activity after a malicious document has been executed.

这些包含恶意软件的PPT文件一旦被打开立即向电脑投下恶意软件，以下的截图显示了恶意文档被执行之后的进程活动情况。

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There is a wine that once opened, will still taste fresh and fabulous decades later.

FORBES: Why Madeira Is The Next Great Thing In Wine

Once opened it forwards itself using the personal and business address books of e-mails so the spread is rapid.

BBC: You are in: UK

And once we opened the court up, we could get into the lane and make plays and fire up shots.

NPR: Thunder Holds Off Clippers To Win 108-104