The compound present perfect subjunctive

The English present perfect indicative (have sung) resembles both the Spanish present perfect and the compound present perfect subjunctive, which may be used to express opinions, expected situations or actions, past actions or situations related to the present, and future situations or actions that may happen or not. The Spanish compound present perfect subjunctive is triggered by relative pronouns, such as que, cuando, quien, and cuanto, or other words, such as quizá, and formed with the present subjunctive of the verb haber (haya) + the past participle of the verb that describes the action or state. Following are the primary uses of the compound present perfect subjunctive:

-To describe an action or situation that should have happened yet its coming to fruition is unknown.

Quizá los alumnos ya hayan terminado el examen.

-To describe actions or situations that should happen in the future yet are uncertain.

Ojalá que haya conseguido empleo para fin de año.

-To express an opinion, wish, or something expected

Espero que mi hermano haya llegado bien a casa.

-To form the negative belief of a certainty that is expressed using the indicative mood.

Positive compound present perfect indicative: Han salido de fiesta.

Negative compound present perfect subjunctive: No creo que hayan salido de fiesta.