Here are some interrogative statements which are right/wrong (both in American and British English).


  1. What took you so long?
  2. Who killed my friend?
  3. What disease took away my dog?
  4. Who committed treason against his country?
  5. What language has the vowel 'oe'?
    What language does not have the vowel 'oe'?


  1. What did take you so long?
  2. Who did kill my friend?
  3. What disease did kill my dog?
  4. Who did commit treason?
  5. What language does have the vowel 'oe'?

Correct me if I am wrong. What grammatical rule each of these interrogative sentences falls into? Hold on a second, I suddenly realized something.

6) Right- What rule each of these sentences falls into?
6) Wrong- What rule does each of these sentences fall into?

7) Right- Which one of you wants to go to prison?
7) Wrong- Which one of you does want to go to prison?

Is this rule called third person “wh” question? What is this rule?

  • 1
    Your "wrong" questions are not necessarily wrong. Consider this exchange: "It took you a long time to get here. You probably stopped off at the pub on the way." "No, I didn't!" "Okay, then what did take you so long?" With the emphasis on "did", it makes the question about finding the correct answer after an incorrect one has been suggested. At least, that's the way I would interpret it. Commented Jul 20, 2018 at 23:26
  • 1
    Also 6 wrong - wrong. "What rule does each of these sentences fall into?" Commented Jul 20, 2018 at 23:30
  • The only sentence above that's wrong is "6) Right".
    – Hot Licks
    Commented Jul 21, 2018 at 12:21

3 Answers 3


The relevant rules are:

  1. In a WH question, invert the subject and the verb (or auxiliary) unless the WH item is the subject.

  2. When inverting a subject and a verb which does not have an auxiliary, use an appropriate part of do as an auxiliary (unless the verb is a form of be or, for some speakers, have).

  3. Do may be used even when the subject and verb are not inverted, for emphasis or contrast. It is very unusual for a WH question to be an appropriate environment for such emphasis or contrast.


When the required answer is the subject (someone or something who does the action), we should not use the auxiliary verbs, 'do', 'does', 'did'.

But, we can use 'will', 'have', 'has', and be verbs e.g. : Who will help your friend? Who has stolen my wallet? Who is speaking?


Nos 2 & 3 on your 'wrong' list are basically the same and needn't be wrong. If your dog suffered from a number of illnesses and the vet is merely explaining to you how ill your pet was and discussing the diseases, you may get impatient and ask: Well, but what disease DID kill my Dingo? Note: if the vet gives you a complete list, then your question should start with "Which" but if he is more vague (possibly trying to impress you and increase his fee), then "what" is OK.

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