nitrogen

空气中大约78%的成分是氮气。

About 78% of the air consists of ___nitrogen.

这些植物需要额外的氮肥来促进生长。

These plants need extra ___nitrogen to enhance their growth.

我们呼吸的空气中约78%是氮气。

About 78% of the air we breathe is ___nitrogen.