3 sentences

1. 这种不稳定的同位素会产生β射线。

   zhè zhǒng bù wěn​dìng de tóng​wèi​sù huì chǎn​shēngβ shè​xiàn.

   This unstable isotope produces beta rays.

   Source: Dong Chinese Dictionary

2. 科学家利用这种同位素来研究地质年代。

   kē​xué​jiā lì​yòng zhè zhǒng tóng​wèi​sù lái yán​jiū dì​zhì nián​dài.

   Scientists use this isotope to study geological time.

   Source: Dong Chinese Dictionary

3. 科学家通过观察同位素的蜕变来确定岩石的年代。

   kē​xué​jiā tōng​guò guān​chá tóng​wèi​sù de tuì​biàn lái què​dìng yán​shí de nián​dài.

   Scientists determine the age of rocks by observing the radioactive decay of isotopes.

   Source: Dong Chinese Dictionary