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 verdict was murder by a person or persons unknown.

裁断是一人或多人谋杀，凶手身份未明。

《牛津词典》

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》

Not only did the always interesting Lady Gaga show up inside a large egg-like structure, but unknown artists also won top prizes.

VOA: special.2011.02.18

There's only one unknown a.

所以只有一个未知量,a

耶鲁公开课 - 基础物理课程节选

A kind of a pin used to hold your cloak together, called a fibula, unknown in the previous period.

一种别住披风的别针,称之为扣针,这在之前的时期从未出现过

耶鲁公开课 - 古希腊历史简介课程节选

Now the former church worker wants to give another unknown a chance of fame.

BBC: Singer Susan Boyle in search for next star for duet

The new ship will also have amenities unknown a century ago, like air conditioning.

WSJ: Billionaire launches plans for Titanic replica

The cause of a massive gas explosion that destroyed three homes is still unknown a year after the incident.

BBC: Rosehill Street gas blast cause still unknown