Tu dois me prévenir avant de partir.

You must let me know before leaving.

Breakdown of Tu dois me prévenir avant de partir.

• tu: you
• avant de: before
• partir: to leave
• devoir: must
• me: me
• prévenir: to let know

Questions & Answers about Tu dois me prévenir avant de partir.

What does prévenir mean here? Does it mean to prevent?

• Here prévenir means to warn, inform, or let someone know in advance.
• With a person as the object (e.g., me prévenir), it does not mean to prevent. To express prevent (someone from doing something), use empêcher: m'empêcher de partir.
• Note: prévenir can mean prevent only with impersonal/non-human objects: prévenir un accident (to prevent an accident).

Why is it me prévenir and not prévenir moi?

• French uses unstressed object pronouns (me, te, le, la, lui, nous, vous, leur, y, en) before the verb they belong to. Here, the object belongs to the infinitive prévenir, so it comes right before it: Tu dois me prévenir.
• moi is the stressed pronoun and isn’t used as a direct object before the verb. It appears after prepositions or with the affirmative imperative: Préviens-moi.
• In the negative imperative, the pronoun goes before the verb again: Ne me préviens pas.

Why is prévenir in the infinitive after dois?

• devoir here is a modal/semi-auxiliary (must/have to) and is followed by an infinitive.
• Only devoir is conjugated; the action verb stays in the infinitive: Je dois te prévenir, Ils devront nous prévenir.

Where do pronouns go in negatives and questions with this structure?

• Negation wraps around the conjugated modal: Tu ne dois pas me prévenir.
• Inversion question: Dois-tu me prévenir avant de partir ?
• With est-ce que: Est-ce que tu dois me prévenir... ?
• With another pronoun like en: Tu dois m'en prévenir (warn me about it). In the affirmative imperative, the order switches and forms elide: Préviens-m'en.

Why avant de? Can I say avant partir or avant à?

• The correct pattern is avant de + infinitive: avant de partir. You cannot drop de, and avant à is incorrect.
• Before a noun, use avant + noun: avant ton départ.
• Elide before vowels: avant d'arriver.

When do I use avant que instead of avant de?

• Use avant que + subjunctive when the subject of the second verb is different: Préviens-moi avant que je parte.
• If the subject is the same, use avant de + infinitif: Tu dois me prévenir avant de partir.
• Formal note: after avant que, French often adds an expletive ne: avant que tu ne partes.

In avant de partir, who is leaving?

• The implied subject of partir is the same as the main clause subject: here, tu.
• To say before I leave, use avant que + subjunctive: Préviens-moi avant que je parte.

Why use partir and not quitter?

• partir is intransitive and stands alone: partir (to leave).
• quitter is transitive and needs a direct object: quitter la maison, quitter son travail.
• So: avant de partir but avant de quitter la maison.

Can I use s'en aller instead of partir?

• Yes, slightly more colloquial: Tu dois me prévenir avant de t'en aller.
• Note the internal pronouns with the infinitive: de t'en aller.

Is me a direct or indirect object with prévenir?

• With prévenir, the person warned is a direct object: prévenir quelqu'un. So me is direct here.
• This affects past participle agreement with avoir: Elle m'a prévenu (speaker male) / Elle m'a prévenue (speaker female).

How do I add what I’m being warned about?

• Pattern: prévenir quelqu'un de quelque chose → Tu dois me prévenir de ton départ.
• Replace de + thing with en: Tu dois m'en prévenir.
• Affirmative imperative order and elision: Préviens-m'en.

Is Tu dois... too strong? How can I soften it?

• Softer or more polite options:
  • Tu devrais me prévenir... (you should)
  • Il faudrait me prévenir... or Il faut me prévenir...
  • Merci de me prévenir..., Pense à me prévenir...
  • Formal/plural: Vous devez / Vous devriez me prévenir...