These expressions, which can replace "si," add different nuances to the expression of conditions.
À Condition De
Used to stipulate a necessary condition for the fulfillment of an action.
- Vous pouvez réussir, à condition de travailler dur. (You can succeed, provided you work hard.)
- Il viendra, à condition de recevoir une invitation. (He will come, provided he receives an invitation.)
Pourvu Que
Expresses a wish or a hoped-for condition for something to happen. Often used with the subjunctive.
- Nous irons pique-niquer demain, pourvu qu'il fasse beau. (We will go picnicking tomorrow, provided the weather is nice.)
- Pourvu qu'il n'y ait pas trop d'embouteillages, nous arriverons à Paris avant dix heures. (Provided there isn’t too much traffic, we will arrive in Paris before ten o'clock.)
En Cas De
Indicates a hypothetical condition, often used to talk about precautions or measures to be taken.
- En cas de pluie, prenez un parapluie. (In case of rain, take an umbrella.)
- En cas de panne, contactez le service d'assistance. (In case of a breakdown, contact the assistance service.)
Tant Que
Means "as long as" and is used to express the duration of a condition.
- Vous pouvez rester tant que vous le souhaitez. (You can stay as long as you want.)
- Je te soutiendrai tant que tu en auras besoin. (I will support you as long as you need it.)
Aussi Longtemps Que
Similar to "tant que," it expresses the duration during which an action remains valid or a condition is maintained.
- Je continuerai à essayer, aussi longtemps que c'est possible. (I will keep trying as long as it’s possible.)
- Nous resterons ici, aussi longtemps que le soleil brillera. (We will stay here as long as the sun is shining.)