He has applied to join the army.

他已报名参军。

《牛津词典》

The son left to join the army.

儿子去参军了。

youdao

He sent his son to join the army as soon as he reached eighteen.

他儿子一满18岁，他就送他参军了。

《新英汉大辞典》

If a drafted man could not do either thing, then he must join the army or be shot as a deserter.

VOA: special.2009.10.29

Most men should try and join the army, you know.

大部分男人应该试着加入军队。

想当军人的理由 - SpeakingMax英语口语达人

How do you join the army in the United States?

在美国怎么样才能入伍？

关于美军 - SpeakingMax英语口语达人

He said Drummer Rigby's dream had been to join the army when he was growing up.

BBC: Drummer Lee Rigby: Family's 'hearts ripped apart'

"I always wanted to join the Army right from I was a boy, " he said.

BBC: Ballymena soldier Phillip Gillespie back to fitness

Anyone arrested or imprisoned, or who seeks to join the army or police, is scanned.

ECONOMIST: Biometric data and the Afghan war