Breakdown of Tu n'aurais pas choisi ce parcours.
tu
you (informal singular)
avoir
to have
ne
not (used before the verb)
pas
not (used after the verb)
Questions & Answers about Tu n'aurais pas choisi ce parcours.
How is the past conditional formed in this sentence?
Just like the passé composé, it is a compound tense. You take the auxiliary verb (avoir or être) and put it in the conditional, then add the past participle. Since choisir uses avoir, we conjugate it to tu aurais and add the past participle choisi.
Why does pas come before choisi?
In compound tenses like the past conditional, the negation (ne... pas) goes around the conjugated auxiliary verb, not the whole verb phrase. So it surrounds aurais, making it tu n'aurais pas choisi, exactly like how you would say tu n'as pas choisi in the passé composé.
Would choisi change if the person being spoken to is female?
No. Because the auxiliary verb is avoir, the past participle choisi does not agree with the subject (tu). It would only change if there was a preceding direct object.