Explanation: Nearly 50 million light-years away in the constellation Ursa Major, NGC 4013 was long considered an isolated island universe.是什么意思_Explanation: Nearly 50 million light-years away in the constellation Ursa Major, NGC 4013 was long considered an isolated island universe.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句