YOU SAID:
Dot they know it is christmas?
INTO JAPANESE
彼らはそれがクリスマスだと知っていませんか?
BACK INTO ENGLISH
Don't they know it's Christmas?
INTO JAPANESE
彼らはそれがクリスマスだと知らないのですか?
BACK INTO ENGLISH
Don't they know it's Christmas?
You've done this before, haven't you.