"When did you go there?" vs "When you went there?" [closed]

You can make an IN SITU question by making a normal sentence and replacing the information you don't know with a wh- word:

1. You're meeting who?
2. You can see what?
3. You went there when?

If you want to make a normal question, you need to move the wh- word to the beginning of the sentence. In this situation, you will need to use subject-auxiliary inversion. The subject and auxiliary will change places after the question word:

• Who are you meeting?
• What can you see?

In example (3), the in situ question has no auxiliary verb: You went where?. We cannot use went as an auxiliary verb. We need a proper auxiliary. In this situation, we need to use the auxiliary verb DO:

• When you went there? (wrong)
• When did you go there?

Note: Notice, though, that if the wh- word is already at the front in the in situ question, we do not need to use subject auxiliary inversion:

• Who went there?

The question is about turning statements into questions. There are lots of ways, and different kinds of resulting questions. It makes the most sense to me if it's looked at on two levels:

1. Yes/No Questions -- The lower level, with binary possibilities only.
   • Several offshoots, including Neg-swap tags
     He saw her, didn't he? / He didn't see her, did he?
     Some features (starting with a sentence in the present or past tense)
   • Y/N questions normally have subject-auxiliary inversion
     (He is going => Is he going?)
   • Inverted Y/N questions take Do-Support if there's no auxiliary
     (He went => Did he go?)
   • Y/N questions have rising intonation at the end
     (symbolized by a question mark in writing)

So the rule for forming a Y/N question is:

• If there isn't an auxiliary, insert do and change the main verb to an infinitive form.
• Move the auxiliary verb (or do, if it's been supplied, in front of the subject.
• Add question intonation at the end.

(By the way, this is just a description of how sentences are arranged, and related to one another. It doesn't represent -- it isn't intended to represent -- what speakers actually do when they talk.)

2. Wh- Questions -- Higher level, specific information, uses the Y/N rule above.
       Several offshoots, including In Situ questions, as @Auraucaria points out.
       Some features (starting with a sentence in the present or past tense):
       • Wh-questions always contain a Wh-word specifying the information requested
         -- who, what, which, when, where, why, how (plus whether; whence, whither,
           whereof, wherewith, etc. are obsolete forms of where)
       • If the Wh-word is the subject, Stop.
         The In Situ question is a correctly-formed Wh-question.
       • Otherwise, form a Yes/No question (using the rule in part 1)
         from the In Situ question. (including Do-Support, as needed)
       • Then move the Wh-word to the beginning of the question,
         before the fronted auxiliary verb.

So the rule for a Wh-question is

• Insert the Wh-word for the unknown information (He saw X => He saw who)
• If the Wh-word is the subject, Stop (add a question mark if writing).
• Otherwise, make a Y/N question, using the rule in part 1
      (He saw who => Did he see who)
• And move the Wh-word to the front (Did he see who => Who did he see?)