The verb is, do, does

 

Witch is who 'witch do' does.

Without translating explain what is 'is', 'do' and 'does', and see the difference of do and does, here does was verb inflexion and do is a verb but the in the phrase is a substantive that means done, and in the phrase is the object and the second witch is in the phrase is adjective of do and the first witch is substantive and in the phrase is the person of the discourse if you know all that you are good in Grammar. Rute Bezerra de Menezes Gondim