Using radiometric dating methods, Sugden determined that the ash settled into the fissure after a volcanic eruption 8.1 million years ago.是什么意思_Using radiometric dating methods, Sugden determined that the ash settled into the fissure after a volcanic eruption 8.1 million years ago.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句