But the Chinese farmers used six times more nitrogen, and produced almost twenty-three times more surplus nitrogen.

VOA: special.2009.07.28

Here is the second nitrogen, one, two, three, four, five.

这是第二个氮，一二三四五。

麻省理工公开课 - 固态化学导论课程节选

Here is the second nitrogen, one, two, three, four, five.

这是第二个氮，一二三四五。

麻省理工公开课 - 固态化学导论课程节选