The document discusses the present perfect simple tense in English. It explains that the present perfect tense is used to talk about actions that happened at an unspecified time before now. It lists common time expressions used with the present perfect tense, such as ever, just, already. It then describes the basic form of the present perfect tense, which is subject + have/has + past participle verb. Finally, it notes an exception for irregular verbs, which take their irregular past form in the present perfect tense.