Breakdown of C'est injuste qu'il ait obtenu cette augmentation.
il
he
avoir
to have
ce
this (before a noun)
c'est
it is, that is
Questions & Answers about C'est injuste qu'il ait obtenu cette augmentation.
How is the past subjunctive formed in ait obtenu?
The past subjunctive is a compound tense. You form it by taking the present subjunctive of the auxiliary verb, which is avoir here (giving us ait for il), and adding the past participle of the main verb (obtenir becomes obtenu).
Why use the past subjunctive (ait obtenu) here instead of the present subjunctive (obtienne)?
We use the past subjunctive to show that the action in the que clause happened before the emotion or judgment in the main clause. The judgment (it is unfair) is happening now, but he already got the raise in the past. If he were getting the raise right now or in the future, you would use the present subjunctive: qu'il obtienne.
What makes C'est injuste que a subjunctive trigger?
Expressions that show a subjective judgment, opinion, or emotion always trigger the subjunctive. Since saying something is injuste (unfair) is a personal judgment rather than a statement of objective fact, the verb that follows it must be in the subjunctive mood.