We use "didn't" before the main verb. The structure of a negative sentence in past simple is similar to an affirmative sentence, first, write the subject or pronoun, then, "didn't" followed by the main verb, it goes in base form, and finally the complement and the time expression. Examples:
We use the auxiliary "Did". It goes at the beginning of the sentence, it is followed by the subject or pronoun, the main verb goes in base form and finally, write the complement and the time expression. Let's see some examples:
Other rule is for verbs ending in -e, we only have to add -d. For example:
dance - danced
love - loved
hate - hated
Verbs ending in a consonant, preceded by a vowel and this vowel is preceded by a consonant, we have to double the last consonant and add -ed. For example: