In the only other supernova remnant (the Vela supernova remnant) where such features have been observed, the crescent shapes are clearly produced by ejecta fragments.是什么意思_In the only other supernova remnant (the Vela supernova remnant) where such features have been observed, the crescent shapes are clearly produced by ejecta fragments.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句