=Anno Domini [拉]公元【说明】A.D. 应该写在年数之前, B.C. 应该写在年数之后, 如: from 300 B.C. to A.D. 400 由公元前三百年到公元四百年
公元
1. in the Christian era; used before dates after the supposed year Christ was born; "in AD 200"
(synonym) ,
ad (n.) 公元...ad (n.) 广告...addition (n.) 增加；加
somewhere...ad.在某处，到某处...son
according...ad.按照；根据...across
yet...ad.到目前为止，还；仍然...you
1. in the Christian era; used before dates after the supposed year Christ was born; "in AD 200"(synonym) , 
现代英汉综合大辞典
