Question

can someone explain me the AD and BC concept

Answer 1

AD means anno domini
BC means before crust of jesus

Answer 2

The tearm anno Domini stand for (AD) and before Christ stand for (BC) are used to label or number years in the Julian and Gregorian calendars. ...
However, BC is placed after the year number (for example: AD 2018, but 68 BC), which also preserves syntactic order.