carbon

钻石是由碳形成的。

Diamonds are formed from ___carbon.

这辆跑车的轮毂采用轻质碳纤维材料制成，以提高速度性能。

The sports car's rims are made of lightweight ___carbon for better speed.

温室气体包括甲烷和二氧化碳。

Greenhouse gases include methane and ___carbon dioxide.