군대는

the military

→ 군대
phrase Rare #25,090
the military 군대 means “the military” or “the army,” and 는 is the topic marker. In 군대는 갔다 왔다, the phrase commonly refers to completing military service.
KO: 그는 군대는 다녀왔어요.
EN: He completed his military service.

군대는 갔다 왔지

You did serve in the military, right?

— 버닝 (2018)

하지만 군대는 무서워

But the military is scary.

— 학이 난다 (1957)

섭정 으로서 여길 지킬 의무가 있어요 군대는 어디 있습니까?

As regent, I have a duty to protect this place. Where is the army?

— 반지의 제왕: 왕의 귀환 (2003)