The document discusses the use of the past simple tense in English. It provides 3 key points: 1) The past simple tense is used to describe completed actions that occurred at specific times in the past. It involves conjugating verbs to their past form and can be used with time adverbs like "yesterday". 2) Regular verbs are conjugated to the past by adding "-ed" while irregular verbs do not follow patterns and must be memorized. 3) Affirmative sentences in the past simple follow the formula S+V2+C where the verb is in the past tense. Negative sentences use "didn't" between the subject and main verb.