On the contrary, if XML documents are received from an unknown source, be careful to validate XML documents to maintain data integrity.

相反，如果从未知源获取XML文档，则要验证XML文档以维护数据的完整性。

youdao

You have received an update from an unknown source.

您已收到一个未知来源的更新。

youdao

Cosmic rays are being produced close to Earth from an unknown source.

宇宙射线由一个未知来源在地球附近产生。

youdao

As the monitors were leaving the area, an unknown source fired at three vehicles, she said.

CNN: STORY HIGHLIGHTS

It is probable that it has an animal source, but whether it spreads from contaminated food or something else in the environment is unknown.

BBC: Threat from novel coronavirus 'remains low'