6 Comments
Technically you are certain is not a question. There is no question word to indicat a question. It is a statement
December 24, 2015
If you follow it with a question mark and raise the intonation at the end of the sentence it is a question.
March 1, 2019
Yes, in fact this is how they ask questions in Portugal all the time. Are you certain? should be accepted.
April 1, 2016
