服役的英文：
serve in the army
be in active service

参考例句：

Be in the service
在部队服役

I served 22 years in the United States marine corps.
我在美国海军陆战队服役了22年。

We used to use this trick in the Army to simulate illness.
我们在军队服役时惯常用这一伎俩装病。

Serve in the U.S. air Force
在美国空军服役

put into commission; equip for service; of ships.
使服役；为……服役；用于指船。

Jack up discipline among the servicemen
加强服役人员的纪律性

He is attached to a destroyer
他在一艘驱逐舰上服役。

To enroll compulsorily into service; draft.
征兵被强迫征募服役;征兵

Some wartime vessels are still in commission.
有些战时的军舰仍在服役.

Compulsory enrollment in the armed forces;conscription.
征兵军队的义务服役的注册;征兵

serve是什么意思：
v. 为...服务；供应；任（职）；服役
n. 发球（权）

to serve the landlord
为地主干活

Persons serving on the Appellate Body shall serve in rotation.
上诉机构人员任职应实行轮换。

They drafted him to serve as their delegate.
他们选派他作他们的代表。

army是什么意思：
n. 军队；陆军；军团；大群；团体

a standing army
常备军,5. 固定的,不能移动的,6. 【印】(版面)排好后保留的,n.1. 站立[U]2. 站立处[C]3. 身份;地位;名望[U]4. 名次表[P]5. 持续时间[U]

The army policed the conquered city.
军队管制这个被占领的城市。

The general directed the army to attack.
将军指挥军队进攻。

active是什么意思：
adj. 活跃的，积极的；现行的；主动的
n. 积极分子

She is an active participant in this activity.
她积极参与这项活动。

They are union actives.
他们是工会积极分子。

contamination activity
污染放射性