帮忙翻译一下（英译汉）

An unidentified flying object, or UFO, is any real or apparent flying object which cannot be identified by the observer and which remains unidentified after investigation. The term flying saucer is also sometimes used, although the two terms are not genuinely interchangeable.

Reports of unusual aerial phenomena date back to ancient times (see Ancient astronaut theories), but modern reports and first official investigations began during World War II with sightings of so-called foo fighters by Allied airplane crews and in 1946 with widespread sightings of European ghost rockets. UFO reports became even more common after the first widely publicized United States sighting in 1947. Many tens of thousands of UFO reports have since been made worldwide. [1] Many sightings may remain unreported due to fear of public ridicule because of the social stigma surrounding the subject of UFOs and because most nations lack any officially sanctioned authority to receive and evaluate UFO reports.

Once a UFO is identified as a known object (for example an aircraft or weather balloon), it ceases to be classified as a UFO and is reclassified as an identified object.

一个不明飞行物，还是飞碟，是任何真正的或明显的飞行物体，不能确定的观察员和调查后仍然不明。飞碟一词有时也使用这两个词虽然不是真正互换。

空中异常现象报告可以追溯到远古时代（见古代宇航员理论），但现代的报告和第一次正式的调查始于第二次世界大战期间与所谓的盟军飞机机组人员富战士，并与欧洲的幽灵在1946年普遍目击目击火箭。 UFO报告变得更为普遍，在第一次广泛宣传，美国在1947年发现。 UFO报告的几万，至今已在世界范围内。 [1]许多目击可能仍然未报告的，由于害怕，因为社会围绕不明飞行物问题公开嘲笑和羞辱，因为大多数国家缺乏任何官方批准的机构接受和评估UFO报告。

一旦飞碟是一个已知的对象确定（例如飞机或气象气球），它不再被列为不明飞行物，并重新分类为被确定的对象。

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