Many unusual signals from space remain unidentified.

许多来自于太空的不寻常信号都尚未确认。

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All the cultural relics of Chinese origin, or of unidentified origin, or of foreign origin that remain in the Chinese inland waters and territorial waters;

遗存于中国内水、领海内的一切起源于中国的、起源国不明的和起源于外国的文物；

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An unidentified plane has crashed to the ground and exploded in eastern China, state media reports, but the accident remains shrouded in mystery and potential casualties remain unknown.

一架身份不明的飞机坠落到中国东部地区的地面，中国国家媒体报道其发生了爆炸，但事故仍然笼罩在神秘之中，潜在的伤亡目前仍然不明。

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Despite a nationwide manhunt, the boys remain unidentified by everyone except their parents.

ECONOMIST: New fiction

About 9, 000 human remains recovered from the ruins of the World Trade Center remain unidentified because they are too degraded to match victims by DNA identification.

WSJ: Possible human remains found in new 9/11 debris