Definition
To enlist and become a part of the military services.
参军；入伍
After the country declared war, many people decided to join up.
在国家宣战后，许多人决定参军。
He joined up at the age of 18, hoping to serve his country.
他在18岁时入伍，希望为国家服务。
She encouraged her friends to join up to gain more life experience.
她鼓励她的朋友参军以获得更多人生经验。