once; already; former; previously; ever; (past tense marker used before verb or clause)[cedict]
担任
dān rènㄉㄢ ㄖㄣˋ
to hold a governmental office or post; to assume office of; to take charge of; to serve as[cedict]
过
guòㄍㄨㄛˋ
(experienced action marker); to cross; to go over; to pass (time); to celebrate (a holiday); to live; to get along; excessively; too-; surname Guo[cedict]
边境
biān jìngㄅㄧㄢ ㄐㄧㄥˋ
frontier; border[cedict]
保安
ān ㄢ
bǎo ānㄅㄠˇ ㄢ
Baoan ethnic minority[cedict]
to ensure public security; to ensure safety (for workers engaged in production); public security[cedict]