secondary isotope

例句：

1. 1. The study of isotopes is crucial for understanding the originsof life on Earth.
   研究同位素对于理解地球上生命的起源至关重要。
2. 2. The team useda mass spectrometer to analyze thesecondary isotope ratios in thesample.
   该团队使用质谱仪分析了样本中的次级同位素比率。
3. 3. Theresearcher discovered that certain elements have secondaryisotope variations that can be usedto trace their origins.
   研究者发现某些元素具有次级同位素变化，这些变化可以用来追踪它们的来源。