did is the past tense of 'do.' It can be used when describing an action in the past. The verb does not have any special meanings but it is often used when talking about a completed action. As an auxiliary verb did is used with main verbs to form questions, or used with not to form negatives.
I did my homework last night. (verb)
She did her best. (verb)
We did a lot of exploring on the trip.(verb)
Did you have a good time? (auxiliary verb)
I did not go to the party. (auxiliary verb)
Did she tell you what happened? (auxiliary verb)
it is important to note that when forming a question with 'did,' the auxiliary verb always comes first, followed by the subject (example Did you do it?), rather than the main verb first followed by the subject (example You did it?). Another mistake to watch out for is when using 'didn't.' 'Didn't' is used for negative sentences and has the same structure as 'did' but with 'n't' added on the end (example She didn't do the dishes). When using the auxiliary verb 'did,' it is important to pay attention to the subject of the sentence. If the subject is third person singular, you would use a 'did' form rather than a 'do' form.