The focal plane of the light is 200 feet above mean sea level, and in clear weather it should be seen at a distance of 23 nautical miles.是什么意思_The focal plane of the light is 200 feet above mean sea level, and in clear weather it should be seen at a distance of 23 nautical miles.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句