Did she use to or Did she used to?
Dr. Irvin Yalom has answered my question about why he wrote "Did she used to..." in his The Schopenhauer Cure . The correct form is "Did she use to..?" and the answer to the "error" is a phonetical one: The sound of the "t" blends with "use" to make it sound "used" and inadvertedly people fall into this grammatical ditch. A liaison that may sound far-fetched, but which is not. Try it. This answer does satisfy me. And I thank Dr. Yalom for his quick reply.