Many people enlisted for the defense of their country.
许多人为了保卫国家而从军了。

He is pining to go into the army.
他渴望从军。

Are you saying I should give up trying to be a soldier?
你的意思是说我应该放弃从军的打算？

In order to Hua Mu Lan rescue her the father therefore joined the army.
花木兰为了救她的父亲所以去从军了。

Fortunately, our Armed Services is—the young men and women who participate, they believe so strongly in their service to their country that they are willing to go.
幸运的是，我们的武装部队——这些从军的年轻人——他们坚信为国奉献，自愿去前线。

You actually went off and practiced geology. All I ever did was hide behind rocks during my military career.
您曾身体力行从事地质工作，而我所做的只是在从军期间利用岩石作掩护。

He enrolled himself in the army.
他从军了。

The experience in army is helpful to him.
他从军的经历对他很有用。