The document discusses the present perfect tense in English. It provides the form of the present perfect simple as subject + have/has + past participle. It contrasts the present perfect tense with the simple past tense. The present perfect is used for actions that began in the past and continue in the present, or actions that occurred at an unspecified time in the past. The simple past is used for actions that are finished and no longer connected to the present, or actions that occurred at a specific time in the past. The document also lists common time expressions used with the present perfect and simple past tenses.