Auxiliary do

From Teflpedia

Auxiliary do is the use of the English verb "do" as an auxiliary verb.

This is used in both the present tense and past tense, but only with the simple aspect, i.e. present simple and past simple. It is also not used with be, except in the imperative mood.

The auxiliary do can be dropped in some constructions, forming making it a hidden do. Both do and have when used as a lexical verb need an auxiliary do, which can be a little confusing for learners.

As an auxiliary verb it is used to form short answers.

  • Present simple:
    • "Do you like tomatoes?".
    • Yes, I do. No, I don't
    • I don't have a pen.
    • I (do) have a pen.
    • What do you do?
  • Past simple:
    • "Did you like tomatoes?".
    • Yes, I did. No, I didn't
    • I didn't have a pen.
    • I did have a pen (dropped: I had a pen).
    • What did you do?