We use the past simple to talk about actions that happened at a specific point in the past. We use the simple past auxiliary “did”  in questions, negative sentences, and short answers.

Form:

     –  Affirmative: subject + verb (in simple past) + complement / object
     –  Negative: subject + did not/didn’t + verb (in infinitive without “to”) + complement / object
     –  Questions: Did + subject + verb (in infinitive without “to”) + complement / object?

Examples:
     –   Mary worked two hours yesterday.
     –   Mary didn’t work two hours yesterday.
     –   Did Mary work two hours yesterday

     Remember: regular verbs in the past simple end in “-ed”. Irregular verbs change completely or do not change at all.

Regular verbs: 

Irregular verbs:

Practice this lesson here: Past simple exercises, Reading 4, Reading 6, Reading 7