点津:
这三个词没啥关系,只是长得像,大家睁大眼睛不要被蒙蔽了啊!
Radius:半径
He has visited every shop within a radius of two miles.周围两英里以内的店铺他都去过。
Radium :〈化〉镭
Radium can be used to treat cancer.
镭可以用来治疗癌症。
Radiate:发射出(光、热等),向四周伸出
The sun radiates light and heat.
太阳散发光和热。
答案:
radius, radium, radiate