El presente perfecto del subjuntivo

A. Definition :
  
- action or situation that may have occurred
                                       before the action in the main verb.
- the present perfect subjunctive can be used
                                       to express emotion or uncertainty.


B. Forms :


- present subjunctive conjugation of haber + the past participle
- and can be indicated by the presence of "que"

* past participles for present perfect subjunctive are the same as
      the past participles used for other tenses, even the irregular ones.


         haya trabajado               hayamos trabajado
         hayas trabajado
         haya trabajado               hayan trabajado

ex)    Me alegro de que ella haya llegado       
                                                     - I'm glad she has arrived.
        Dudo que ella haya llegado                   
                                                     - I doubt she has arrived.
        Niego que ella haya llegado                  
                                                     - I deny she has arrived.
        Es posible que ella haya llegado            
                                                      - It's possible she has arrived.
        Lo haré después que ella haya llegado     
                                                      - I'll do it after she has arrived.