Question

9) where your father / live 10) what/ sell / Max (Do,Does)

Answer 1

Hi !!

9) where your father / live

  Where does your father live ?

10) what/ sell / Max

   What does Mark sell ?

(Do,Does)

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in the interrogative or negative form, the 's' of the 3rd p. singular is added to the auxiliary "do"

Where do you live ?

I live in New York.

Where does he lives?

He lives in LA.

DO takes the 's' of the 3rd p. singular, and the verb stays as a verb  in base form.

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hope this helps:)