Answer: My second son has good knowledge.
So how to question some one which son (first,second, ...)? Is below sentence correct for the above answer? It's not correct as per me!
Which/what numbered son of you has good knowledge?
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Sign up to join this communityAnswer: My second son has good knowledge.
So how to question some one which son (first,second, ...)? Is below sentence correct for the above answer? It's not correct as per me!
Which/what numbered son of you has good knowledge?
In the US, people don't typically refer to their children in terms of numerical birth order. The more common reference would be oldest, youngest, and middle. It's relatively unusual for families to have more than three children of a specific gender, so that's usually adequate. Even that distinction may or may not be volunteered.
You could construct a question to elicit the information, like "What is the birth order of the son with the most knowledge?", but it would seem like a very strange question. The natural way to get the information would be with two questions; the second in case the information wasn't volunteered in response to the first.
The first could be something like, "Which of your sons is the most knowledgeable?" The answer would likely be something like either, "That would be John", or "That would be my oldest son, John." (Of course you could always get an answer like, "All my sons are dumber than a sack of rocks.")
If the answer was like the first example, the next question would be some coaxing, like "Is he your oldest?" The response would typically be either confirmation or correction. If you were talking with somebody who was not the sharing type, you might get just "Nope." Social graces of going through this "dance" to get information results in it being an arduous process often enough to have its own expression: that getting the information "is like pulling teeth."
If you initially asked something like, "Would you say your oldest son is the most knowledgeable?", you might luck out with a yes. But if that was not the right answer, there's no guarantee of what information you would get in a response (essentially the same situation as the first question, above).
Trying to directly ask for birth order as a qualifier on another question is just culturally strange, so you could create a question to do it, but it would likely be perceived as odd, at least in conversation. The reaction might be different if it was on some type of form that was collecting information for some official purpose or survey.
The simplest form of asking that question is:
Which of your sons has good knowledge?