The present perfect tense is used to express an event that happened in the past without specifying the exact time of its occurrence. In this tense we use (have - has) with the main verb in the past participle. Examples I have studied my lessons. He played football. We notice in the first example that we used the auxiliary verb Have because of the presence of the pronoun I, and at the same time we used the third form of the verb (study), which is (studied), because of the presence of the auxiliary verb in the sentence that occurred in the past tense without specifying the time of occurrence of the verb, which necessitated placing the verb here in the present perfect tense.