Simplify the following text for a Grade 8 native English-speaking person.
Original: Some countries ( such as the United States ) use the General Officer ranks for both the army and the air force ; others only use the General Officer ranks for the army , while in the air force they use Air Officers as the equivalent of General Officers . They use the air force rank of Air Chief Marshal as the equivalent of the specific army rank of General .
Simplified: A general officer is an officer who is at a high military rank , usually in the army , and in some places , the air force .