Q. We want to know the usage of “etc.” at the END of a sentence, that is, as the last word of a sentence. Is it spelled out?
A. The expression “et cetera” is rarely used. Its abbreviation “etc.” is discouraged in formal writing; CMOS recommends that, if used, it should be confined to parenthetical material or lists and tables. There is, however, no difference between the abbreviation and the two-word Latin expression it represents, and the position in a sentence has no bearing on which is more appropriate. For the use of commas with “etc.” and some of its English equivalents, see CMOS 6.20.
[This answer relies on the 17th edition of CMOS (2017) unless otherwise noted.]
Q. Do you recommend the use of BCE (Before the Common Era) and CE (Common Era) instead of BC and AD? Has the debate about these
been settled or is it still in flux?
A. We are not aware of any intense debate. The choice between one or the other is up to the writer and should be flagged only
if the customs of a specific field or community seem to be in danger of being (unwittingly) violated. Many authors use BC
and AD because they are familiar and conventionally understood. Those who want to avoid reference to Christianity are free
to do so.
[This answer relies on the 17th edition of CMOS (2017) unless otherwise noted.]