Since

The "Since when" question is an idiom that expresses a surprised or sarcastic "Never!" As far as I have observed, it doesn't occur with the continuous.

Someone mentions that they are doing homework or that they are going to do homework.
The surprised and/or sarcastic reply is

Since when do you do homework?

meaning "You never do homework!", the speaker thinkin

Neither is correct. Try: Since when you [do homework]/ [brush your teeth before breakfast] ? This is something you may say to someone when he claimed something that he never did.

dimsumexpressNeither is correct.

What's wrong with the first one?

Hello Aspara Gus . how are you doing? Didn't see you here for a while .
catch you later !

OK, maybe I jumped the gun. Perhaps I got tripped up by how the sentence was formed. You are right. It is grammatically correct. That said, it sounded somehow off beat to my ear. Correct me if I am wrong. In casual conversation, we often t omit the formal "do" for this form of interrogative question, at least to me. Please allow me use a more realistic scenario: The questions below probably will

dimsumexpressJust out of curiosity, if you don't mind, I like to hear your critique on these 5 sentences.

1) Since when you became a 49er fan? incorrect and unnatural
2) Since when have you become a 49er fan? maybe correct but not very natural - borderline
3) Since when do you become a 49er fan? incorrect and unnatural
4) Since

Based on your answers, we definitely don't see things in the same light. I think this could be a case of perception. To me # 1 and # 4 are acceptable and in my opinion grammatical. # 3 semantically, "since when " doesn't seem to pair up well with "do you become a 49ner fan", which is the same issue I have with the original with the "do". If you were a Raider fan for all the years I've known you a