The past simple tense is used to describe actions that were completed in the past. It is formed by adding "-ed" to regular verbs like "work" and "listen" or changing the ending of verbs ending in "y" to "ied", like "study" becoming "studied". There are also irregular verbs that have unique past forms, such as "awake/awoke" and "break/broke". To make a sentence negative, "didn't" is used before the infinitive verb, and questions are formed by placing "did" before the subject and using the infinitive verb.