How do you form the perfect tense in the subjunctive mood and when is it used?

The subjunctive perfect form of a verb is derived in the same way as the indicative perfect form with the auxiliary (être/ avoir) and the past participle of the main verb, except the auxiliary verb is conjugated in the present subjunctive tense. The auxiliary verb used with be exactly the same as that used for the indicative perfect tense. For example, the forms of the verb travailler in the subjunctive past would be as follows:J’aie travailléTu aies travailléIl/elle/on ait travailléNous ayons travailléVous ayez travailléIls/elles aient travaillé The verb aller, which takes the auxiliary verb être would be as follows:Je sois alléTu sois alléIl/elle/on soit allé(e)Nous soyons allésVous soyez allésIls/ elles soient allé(e)sThis tense is used when it is preceded by a subordinating conjunction that triggers the subjunctive mood, such as bien que or il faut que, and where the action being described takes place at a point in the past which is seen as a completed event.