Why Main Verb is Used with did ?

  1. Did is auxiliary verb like Have, Had.

  2. Did represent Tense like auxiliary Had

Then why we use main verb and not past participle with did ~

Example :

  1. Had you changed it ?
  2. Did you change it ?
  • "Changed" is a past participle. Together with a form of the perfect auxiliary verb "have ", it forms the perfect tense, as in your "Had you changed it"? But "Did you change it? is not the perfect tense. It's the preterite (simple past) tense, where "did" is an auxiliary verb requiring the plain form complement "change."
    – BillJ
    Mar 2, 2021 at 9:11
  • Note that the perfect can combine with preterite and present tense,where it is said to have compound tense. The perfect can also occur in clauses without inflectional tense, as in "Ed is said to have spoken fluent Greek", where "have" is in the plain form, so there is no primary tense, no compound tense.
    – BillJ
    Mar 2, 2021 at 9:42

1 Answer 1


It is tempting to say that this is just the way it is and you simply have to learn it, but I think I can do slightly better.

First of all, note that "Did you change" is the past of "Do you change". There is no need for the tense to be encoded twice (on both the auxiliary and main verb), and in any case, perfect and past aren't the same thing (see my second point).

Auxiliary verbs have to be followed by non-finite forms - infinitives or participles. But why one rather the other?

Well, we say "Does he take" (not "Does he takes", which would be ungrammatical) - using the bare infinitive "take". It would be illogical for the past tense counterpart of that ("Did he take") to suddenly switch over from using the bare infinitive to using a participle instead.

The pattern followed by "do" is analogous to that of the modal verbs rather than that of the perfect auxiliary. "He does take", "he must take", "he will take", "he may take", etc.

Secondly, the term "past participle" is a misnomer. The past participle is used for perfects and for passives. "Did you change" and "Did he take" are neither perfect nor passive.

The auxiliary "Have"/"Had" is used to form perfects. The auxiliary "Do"/"Did" is used for emphasis, interrogation or (with "not") as part of a negation.

"Did you change" isn't a perfect, nor a passive, so it would be illogical to use the past participle (once you understand that the past participle is misnamed).

A technical answer: present/past is the primary tense distinction. Nonperfect/perfect is seen by some linguists as a distinction of aspect, by others as a secondary tense distinction. "Have you taken?" encodes present tense and perfect aspect - so we call it the present perfect. "Had you taken?" encodes past tense and perfect aspect. "Do you take?" is present tense and nonperfect. "Did you take?" is past tense and nonperfect.

  • 1
    Cleared , detailed explanation
    – user4084
    Mar 2, 2021 at 7:42

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