for official use only

基本解释

They had a mail service, although it was for official use only.
建立了郵政系統，雖然衹供官方使用。
CUI replaces 100-plus disparate categories of sensitive but unclassified information labels - such as 'for official use only' and 'law enforcement sensitive.
CUI取代了先前的100多種不同非保密敏感信息分類，諸如“僅官方應用”和“法律強制敏感”。
www.etiri.com.cn
The Jan Sangh in 1963 launched a violent agitation for abolishing English not only in official use but in shop signs, street signs and even car number plates.
1963年印度人民黨前身加桑黨發動了一場暴力運動，意圖不衹要廢止官方使用英語，一般商家、車號牌等也不能使用英語標示。

They had a mail service, although it was for official use only.
建立了郵政系統，雖然衹供官方使用。
耶魯公開課 - 新約課程節選