And carbon 14, 6 again and it has 8, and it is found in vanishingly small amounts, 10 10 to the minus 12 or part per trillion.

碳14，6个质子，8个中子，它的存在是非常微小的，几乎趋于零，万亿分之。

麻省理工公开课 - 固态化学导论课程节选

4 And then there are the last four, carbon 14, which is a radioactive form.

然后，还有碳，以放射性形式存在。

麻省理工公开课 - 固态化学导论课程节选