USAF is short for the United States Air Force — the branch of the American armed forces that flies aircraft, and now also handles missiles and much of the military's satellite and space work. You say the four letters one by one, "you-ess-ay-eff", never as a single word.

USAF is short for the United States Air ForceUSAF是United States Air Force（美國空軍）的縮寫 — the branch of the American armed forces that flies aircraft美軍裡負責飛行任務的軍種, and now also handles missiles and much of the military's satellite and space work現在也負責飛彈，還有軍方大部分的衛星和太空業務。You say the four letters one by one這四個字母要一個一個唸, "you-ess-ay-eff"唸成「you-ess-ay-eff」, never as a single word絕不會當成一個單字唸。

It appears mostly in writing: news reports, military documents, the side of an aircraft, a job title like "USAF Colonel James Reed". In speech people are much more likely to say "the Air Force" and let the country be understood from context.

It appears mostly in writing這個字主要出現在書面上: news reports新聞報導, military documents軍方文件, the side of an aircraft飛機機身上, a job title like "USAF Colonel James Reed"或像「USAF Colonel James Reed」這樣的職銜。In speech在口語裡 people are much more likely to say "the Air Force"人們更常直接說「the Air Force」（空軍） and let the country be understood from context讓國別由前後文自己說明。

Note the "the": you say "he joined the USAF", not "he joined USAF", because the full name has "the" in it. Careful — plenty of countries have an air force, so USAF specifically marks the American one, the way ROCAF marks Taiwan's.

Note the "the"注意要加「the」: you say "he joined the USAF"你會說「he joined the USAF」, not "he joined USAF"而不是「he joined USAF」, because the full name has "the" in it因為完整名稱裡本來就有「the」。Careful要小心 — plenty of countries have an air force很多國家都有自己的空軍, so USAF specifically marks the American one所以USAF專門指美國的空軍, the way ROCAF marks Taiwan's就像ROCAF專門指台灣的空軍一樣。