2 Answered Questions for the topic do support
What is the origin of auxiliary verbs?
When and why did we start using auxiliary verbs, particularly *"do"*, to ask questions and make negatives?
What's the negation of "I used to be"? Surely not "I didn't used to be"?
What is the negative form of *"I used to be"*? I often hear *"I didn't used to be"* but that sounds awfully wrong in my ears.