With years, AD is written before the year, and BC is written afterwards.
AD and BCThe abbreviation AD (Anno Domini) denotes of the Christian Era and should be written before the year. The abbreviation BC (Before Christ) should be written after the year.
should be AD 2000
should be AD 71 and AD 109
CATER TO RELIGIOUS DIVERSITY
BCE (Before Common Era) equates to the time before Christ (BC). CE (Common Era) equates to the time after the birth of Christ (AD). They are often used to cater to religious diversity. Both are written after the date.
Full stops (periods) in contractions
Forming the plurals of abbreviations
Using full stops (periods) in abbreviations