Definition: the part of a country's military organization that uses aircraft to fight wars Level: B1
他是一名空军飞行员。
He is an ___air ___force pilot.
白天，你可以参观空军基地，它从9:00开放到6:00。
During the day, you can visit the ___air ___force base, which is open from 9:00 to 6:00.
空军在现代战争中扮演着关键角色。
The ___air ___force plays a crucial role in modern warfare.
