Actually what we call dry ice is frozen carbon dioxide. The atmosphere is very thin and it's nearly all carbon dioxide, so when it gets very cold what condenses out is carbon dioxide snow, carbon dioxide ice.

事实上我们叫做干冰的是冻结的二氧化碳。大气层非常稀薄，几乎都是二氧化碳，所以在它变得非常寒冷的情况下结晶出来的是二氧化碳的雪，二氧化碳的冰。