Spanish/Perfect Subjunctive

Use
The subjunctive mood is used to describe circumstances in which there is doubt, to express emotion, or opinion through the use of impersonal expressions (Es bueno/malo/triste que...) The perfect subjunctive is used in reference to something that happened very recently.

Espero que tú hayas hecho la tarea. I hope that you have done the homework. Es muy triste que ''los niños no hayan escrito sus ensayos. It is very sad that the children have not written their essays.

Formation
The perfect subjunctive is formed by combining the present subjunctive form of the verb haber, meaning to have, with the past participle of the functional verb.

Haber, present subjunctive
 * Yo haya
 * Tú hayas
 * Usted, ella, él haya
 * Nosotros hayamos
 * Vosotros hayáis
 * Ustedes, ellas, ellos hayan