French Phrase
Préviens‑nous à l'avance si tu as besoin de quelque chose.
Meaning
The sentence asks someone to let the speaker (and possibly others) know ahead of time if they need anything. It combines a polite request in the informal ‘tu’ form with a conditional clause that signals a future possibility.
When to use
Use this phrase when you’re offering help or preparing for an event and want the other person to inform you early about any needs—e.g., before a trip, a meeting, or a shared activity.
✦Grammar Breakdown
Préviens-nousàl'avancesituasbesoindequelquechose
Imperative (2nd pers. sing.)
‘Préviens’ is the affirmative imperative of the verb *prévenir* used with ‘tu’.
Pronoun attached to imperative
Object pronouns (here ‘nous’) are attached to the verb with a hyphen in the affirmative imperative.
Adverbial phrase ‘à l'avance’
Means ‘in advance’; placed after the pronoun for natural flow.
Conditional clause with ‘si’
‘si’ introduces a condition; the verb after ‘si’ stays in the present indicative.
Expression of need – ‘avoir besoin de’
Use ‘avoir besoin de’ + noun (or infinitive) to say ‘to need’. Here it is followed by the indefinite pronoun ‘quelque chose’.
Indefinite pronoun ‘quelque chose’
Literally ‘some thing’; used for ‘something’.
🗨In Conversation
Préviens‑nous à l'avance si tu as besoin de quelque chose.
Let us know in advance if you need anything.
D'accord, je vous dirai dès que j’y pense.
Okay, I’ll tell you as soon as I think of it.
✕Common Mistakes
Prévenez‑nous à l'avance si tu as besoin de quelque chose.
‘Prévenez‑nous’ is the formal/plural form; use it only if you’re speaking to several people or in a formal setting.
Préviens nous à l'avance si tu as besoin de quelque chose.
In the affirmative imperative, the pronoun must be attached with a hyphen.
si tu aurais besoin de quelque chose.
The conditional clause should stay in the present indicative after ‘si’; avoid using the conditional mood here.
à avance
Do not omit the article; ‘à l’avance’ is a fixed expression meaning ‘in advance’.
↔Alternatives
Dis‑nous à l'avance si tu as besoin de quoi que ce soit.
Tell us in advance if you need anything.
Fais‑nous savoir à l'avance si tu as besoin de quelque chose.
Let us know in advance if you need something.
Prévenez‑nous à l'avance si vous avez besoin de quoi que ce soit.
Let us know in advance if you need anything. (formal/plural)
Cultural Tip
In French, the informal ‘tu’ form is common among friends, family, or peers, while ‘vous’ would be used in formal or professional contexts. Attaching the pronoun to the imperative (Préviens‑nous) is standard, but remember the hyphen and the change of ‘-s’ to ‘‑s‑’ when the pronoun follows a verb ending in a vowel sound (e.g., ‘Donne‑moi’). Also, French speakers appreciate being told ‘à l'avance’ because it shows respect for planning and courtesy.