The contract was awarded to a previously unknown company.

该合同给了一家先前不知名的公司。

《柯林斯英汉双解大词典》

A previously unknown extremist group has said it carried out Friday's bomb attack.

一个先前未知的极端分子组织声称其实施了周五的炸弹袭击。

《柯林斯英汉双解大词典》

The scientist confirmed the snake was a previously unknown species after conducting a genetic analysis of tissue samples.

在对组织样本进行基因分析后，科学家确认这条蛇是一个此前不为人知的物种。

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The plan follows months of deadlock over Iran's nuclear program and the recent discovery of a previously unknown nuclear-enrichment plant near the Iranian city of Qom.

VOA: standard.2009.10.19

Researchers have determined that dolphins found in southeastern Australia represent a previously unknown species.

BBC: New species of dolphin discovered

By doing so, they can identify previously unknown viruses and perhaps stop them before they spread.

CNN: Tracking deadly viruses' spread from animals to humans

We see on the video a logo of a previously unknown group called the Revenge Brigade.

NPR: Video Released of Kidnapped American Reporter