1.
For the negative and interrogative forms of the "simple past" of the verb "do" as an ordinary verb, it is used as auxiliary "do", e.g. We did not do our homework last night. The negative form of the verb "have" in "simple past" is usually constructed using the auxiliary "do", although sometimes only not or the contraction "not" is added. The interrogative form of the verb "have" in "simple past" usually uses the auxiliary "do".
