Dear Masme
The word since does not mean exactly from. As a preposition, it means from a time in the past until a later time. (One of the lexical definitions says ‘Since when?’ is used when you want to show that you are angry about something). All this, perhaps, implies that since and from are not synonymous with each other.
Now, in the above sentences, I don’t think since is necessary to frame the questions. If, however, you are determined to use it, you should turn the structure into one of present perfect or present perfect progressive. Or you may remove the word since.
Thank you for your reply. However I found a similar sentence in the Cambridge Free dictionary. It is an idiom. I quote: " used angrily in speech why they believe a situation to be different from what it really is or for how long have you believed something."
CFD’s sentence: “Since when do you have the right to tell me what to do?”
I also looked it up in Merriam-Webster. It also says it’s an idiom. They also have more examples, so here its definition and the examples:
—used to show that one is surprised and often angry, annoyed, or doubtful about what someone has said or done"
“I’m a vegetarian.” " *Since when?"
“You told me to do it.” “Since when did you start listening to me?”
"Since when is it okay to cheat?
As you see the second example written in the simple past, so I think that the action started in the past and continues in the past, and perhaps even in the present and future. I think the first and third sentence have the same meaning and therefore I think there’s very little difference in meaning. Altough, I could be wrong, ofcourse.
I have another explanation for this. There are two possibilities, depending on the answer. Native speakers and even some non-native speakers use ‘since when did I or since when do I’ intuïtively correct. I just wondered if there was grammatical rule, concerning this topic, but there isn’t so far as I know.
Dear Masme
I think it is like the AmE using past simple while the BrE uses present perfect as in:
AmE - I just/already had dinner.
BrE - I have just/already had dinner.
The practice (not a rule) in good English is to use the present perfect or the present perfect progressive tense construction when we relate some activity to some specific time in the past and connect it to the present.
This discussion could go on for ages. I think we’ve both said enough about this topic. I’m very grateful for your help, because as always, it’s been very useful. Thank you, my dear friend. Keep yourself and your family very safe as Covid-19 has started a second round. Your life and that of your family’s are worth so much more to me than any damn grammar rule.
