He joined the army in 1781, but he didn't fight in battle.

他在1781年参军，但没有参加战斗。

He joined the army out of his own volition.

他参军是出于自己的意志。

He joined the army because of conscription.

他因为征兵而加入了军队。

He joined the army right after high school.

他高中毕业后就加入了军队。

He joined the army to combat for his country.

他参军是为了为国家战斗。

He joined the army at 18 and became an officer.

他在18岁时参军，并成为了一名军官。

He joined the army at the age of 18 and became a soldier.

他在18岁时入伍，成为了一名士兵。

He joined the army last year.

他是头年参军的.

He joined the army one year ago.

他参军已有一年了。

He joined the army of his own accord.

他自愿地参了军.