They had a mail service, although it was for official use only.

建立了邮政系统，虽然只供官方使用。

youdao

The actual official use that you can make of it is comparing it against null or comparing two USNs for less than, greater than, or equal values.

它的正式用法包括将 USN 与 null 进行比较，或在两个 USN 值之间进行比较，以得出它们的小于、等于和大于关系。

youdao

The consular bag may contain only official correspondence and documents or articles intended for official use and must be sealed and bear visible external marks of its character.

领事邮袋以装载来往公文、公务文件及公务用品为限，应予加封并附有可资识别的外部标记。

youdao

Susan Martimo,a California Department of Education official,says she does not expect widespread use right away.

VOA: special.2009.08.27

They had a mail service, although it was for official use only.

建立了邮政系统，虽然只供官方使用。

耶鲁公开课 - 新约课程节选

You are allowed to use on the test the official version of the Periodic Table of the Elements which most of you should have by now.

在测试中你们可以使用,化学元素周期表的官方版本,你们应该大部分都有了吧。

麻省理工公开课 - 固态化学导论课程节选

Instead it insists to get an eight-digit number labelled "official use" on the hard copy.

BBC: Taxing internet returns

Mazzanti expects the Army will anoint two mobile operating systems for official use.

CNN: U.S. Army may soon equip troops with smartphones

In 2008, following a long debate among judges, he modelled a simplified judicial robe which is now in official use in the civil courts.

BBC: Profiles: UK Supreme Justices