 Re: "Why do you ask?" versus "Why are you asking?"
Why are you asking Tom? He does not know the answer. Ask me instead!
versus
No, I have not seen him lately. Why do you ask?
In both cases, it is a single action happening at or around the time of speaking. Why the difference, then?
Because You, Tom, and the speaker of the words must all be present, and the action is ongoing - hence, the use of the Present Continuous Tense :'are asking'
There is no ACTION in (2). Reference is made to the FACT that a question was asked. Only you (the speaker) and the enquirer are present. |