I'm a non native English learner.I was learning grammar and found repetition of same helping verb in following sentences

  • How do you do?
  • What did you do?

Why there are 2 do/did in such sentences. Can anyone explain me easily. Thanks


1 Answer 1


The auxiliary question "do" is always present in this formulation of a question, regardless of the verb being used:

What did you eat?

How do you know that?

In your sentences, the verb asked about is the verb "to do". Just as above, we use the auxiliary "do" alongside the primary very (which just happens to also be the verb "do"):

What did you do?

How do you do?

Note that auxiliary verbs are not always needed for all questions (see Auxilliary "do" with the subject in questions), but in this case they are needed, and the use of "do" as a primary verb (versus any other verb) does not change that.

  • What about "Why do you do what you do?"
    – Victor B.
    Commented Jan 18, 2018 at 20:17

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