What is radioactive?In the natural world, where the atomic nucleus unstable, can spontaneously emit radiation, some time into other elements atomic nucleus elements called radioelement.是什么意思_What is radioactive?In the natural world, where the atomic nucleus unstable, can spontaneously emit radiation, some time into other elements atomic nucleus elements called radioelement.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句