n.<化>镭(88号元素符号Ra);
例句:
Radioactivity is a special quality of radium.
放射性是镭的一种特性.
To this something still unseen they gave the name radium.
他们给这种人们尚未看到的东西命名为镭.
Radium and uranium are radioactive elements.
镭和铀是放射性元素.