Present vs. past subjunctive

Question

In translating "Before
we moved to the city when I was 13," I used the past subjunctive, "Avant que nous n'ayons emménagé...".  However, you used the present subjunctive, "n'emménagions".  Why is that?

Accepted Answer

Bonjour Helena !
Thank you for this super interesting question, which started a lively conversation in the Kwiziq team :)
In the context of this sentence, Le Subjonctif Présent is definitely the correct option, and here's why:
Le Subjonctif Passé refers, quite similarly to Le Passé Composé, to a "pinpoint" action that started and ended by the end of the statement.
Here's an example: 
Il doit arriver avant que je n'aie repassé mes vêtements.He must get here before I finish ironing my clothes.
-> Here it means before the ironing is finished, completed.
Now in our sentence, "avant que nous n'emménagions en ville", we're not looking at the move as the very action/day of moving, but more as a change of situation, i.e. we used to live there, before we moved/lived here.And that is why Le Subjonctif Présent is the correct option here (as Le Subjonctif Imparfait is completely obsolete nowadays).I hope that's helpful!Merci encore et bonne journée !