The past tense is a grammatical form used to describe actions or events that have already happened. It indicates that something took place before the current moment. For example, in the sentence "She walked to the store," the verb "walked" shows that the action occurred in the past. There are several types of past tense, including the simple past, past continuous, and past perfect. The simple past is often formed by adding "-ed" to regular verbs, like in "He played soccer." Irregular verbs, however, have unique past forms, such as "go" becoming "went." Understanding past tense helps convey time and sequence in communication.