'did not' is a combination of auxiliary verb and negation. 'Did' is an auxiliary verb, also known as a helping verb. In 'did not,' it's used to form the negative past simple tense. The word 'not' serves as the negation. Together, they negate a verb in the past simple tense.
used for forming the negative of the past simple tense, asking negative questions in the past simple tense, and emphasizing a negative statement in the past.
She did not go to the party last night.
Did not you see the sign?
I did not just make that up; it really happened!
'did not' is often contracted to 'didn't' in informal speech and writing. For example, 'She didn't go to the party.' Be cautious about double negatives. Since 'did not' already provides negation, the main verb should be in its base form without any other negatives. For instance, 'She did not go' is correct, while 'She did not didn't go' is incorrect. In questions, the subject and 'did' switch places, but 'not' remains after the subject. For example, 'Did she not go to the party?' This structure can sound formal, and in informal contexts, it's more common to use the contraction
'Didn't she go to the party?'