Some past participles are irregular ... The first part of the perfect tense is the present tense of the verb haber, which is known as an auxiliary verb. An auxiliary verb, also called a helping ...

In your scientific paper, use verb tenses (past, present, and future ... such as an infinitive (to do) or a participle (doing), its subject is implied to be the subject of the clause, or sometimes ...

To form the perfect tense you need a subject, an auxiliary verb and a past participle. Perfect tense with 'être' in French The perfect tense is used to say what you did or have done in the past.