isotopic composition的用法和樣例：
例句
- This paper determined the sulfu risotopic composition of the Mianning REE deposit,Sichuan Province,China.
分析了四川冕寧大型稀土礦床硫同位素組成。 - The second epiphany was that the extracted gas had a significantly different isotopic makeup from what is usually produced in nuclear reactors.
第二項大發(fā)現是，萃取出來(lái)的氣體，同位素組成與一般核反應器中所產(chǎn)生的大不相同。
