Breakdown of Quand la population urbaine aura vieilli, elle diminuera.
elle
she
avoir
to have
quand
when
la population
the population
Questions & Answers about Quand la population urbaine aura vieilli, elle diminuera.
Why does French use the future tense aura vieilli when English just says "has aged"?
In French, when you have a sequence of two future events linked by a time word like quand (when) or dès que (as soon as), the event that happens first must be in the futur antérieur. Since the population must age before it decreases, we use aura vieilli (will have aged). English is looser and often uses the present perfect, but French is strictly logical about future timelines.
Why doesn't vieilli have an extra -e to agree with the feminine subject la population?
Because the auxiliary verb is avoir (aura). With avoir, the past participle never agrees with the subject. It only agrees with a direct object placed before the verb. Since there is no direct object here, vieilli keeps its default masculine singular form.
Why is the pronoun elle used instead of il for "it"?
How is the future tense diminuera formed?