radium

早期的手表使用镭来让表盘在黑暗中发光。

Early watches used ___radium to make the dial glow in the dark.

玛丽·居里发现了镭。

Marie Curie discovered ___radium.

实验室科学家分析氢和镭等元素。

Laboratory scientists analyse elements such as hydrogen and ___radium.