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.

The auxiliary do can be dropped in some constructions, forming making it a hidden do. Both do and have when used as a lexical verbs 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?