回複：回複：回複：我向DOS寄去DS2019和Waiver理由陳述已近1個月

Did Embassy send a "no objection" letter to DOS?
If they haven't, just wait, DOS will not process your case until they get all necessary documents.
If they have, first, go to DOS website and check if there is any document lacking (usually in bold letters). Then go to www.sino-education, find some case numbers that Embassy issued "no objection" one to 3 months earlier than your case. Trace those cases in DOS website, then you can estimate when you will get a final approval. Documents showing up in DOS or not is not a big issue as long as you are sure they got them.