A past participle is a verb form that typically indicates a completed action. It is often used in perfect tenses, such as the present perfect, where it combines with the auxiliary verb have. For example, in the sentence "She has finished her homework," "finished" is the past participle of the verb finish. Past participles can also function as adjectives. For instance, in the phrase "the broken vase," "broken" describes the state of the vase. Regular verbs usually form their past participles by adding -ed, while irregular verbs have unique forms, like go becoming "gone."