Augustine Hancock served as an elementary-school custodian for 20 years.是什么意思？

Augustine Hancock served as an elementary-school custodian for 20 years.

奥古斯丁·汉考克当小学看管人20年了。

Hancock

汉考克（姓氏）；

例句
Herbie Hancock was encouraged by his family to learn music at a young age...
赫尔比·汉考克年幼时家人就鼓励他学音乐。

served

vt.& vi. serve的过去式；v. （为…）服务( serve的过去式和过去分词 )，任（职），提供，端上；

例句
The American served three aces in the opening game of the set.
这位美国选手在该盘首局有三次发球直得。

as

adv. 同样地，一样地，例如；prep. 作为，以…的身份，如

例句
As far as I can recall, Patti was a Smith.
我记得帕蒂是姓史密斯的。

an

art. 一（在元音字母前代替不定代词a），一任一某一，一个；

例句
He started eating an apple...
他开始吃苹果。

custodian

n. 监护人，管理人，保管人，看门人；

例句
a self-appointed custodian of public morals
自封的公共道德的卫道士

for

prep. 为，为了，倾向于，关于，当作；conj. 因为，由于；

例句
I've come looking for a bit of advice.
我特来讨教。

years

n. 年( year的名词复数 )，年纪，一年的期间，某年级的学生；

例句
His wife was sentenced to seven years imprisonment for aiding and abetting him...
他的妻子作为他的从犯被判入狱7年。