The document discusses the present perfect and past perfect tenses in English. [1] The present perfect tense refers to actions that began in the past but continue in the present, and is formed with have/has + past participle. [2] The past perfect tense refers to actions that were completed before some point in the past, and is formed with had + past participle. Both tenses can be used in nominal and verbal sentences, with variations in affirmative, negative and interrogative forms.