Check this 5 min.  video clip that explains fron where the terms B.C. and A.D. derived.

      Check this 4 min.15 sec.  video clip that explains fron where the terms B.C. and A.D. derived.

After you finish taking notes and are working on your homework, if you need help, check this 4 1/2 min. video clip I created to help you put dates on a timeline in both B.C. (B.C.E.) and A.D. (C.E.) areas.