in case

au cas où

Introduit un événement possible auquel on se prépare dès maintenant.

En anglais simple : Do something now because another thing might happen later.

• Take a coat in case it gets cold.
• I saved a copy in case my computer failed.
• Should we buy extra food in case more guests come?

Comment l'utiliser : in case + clause (Take your keys in case I leave early.)

Synonymes : as a precaution against the possibility that

Expressions courantes : just in case, in case something happens, in case it rains

si, au cas où

Introduit une situation dont dépend ce qui se passera ensuite.

En anglais simple : Use this to say what will happen if a particular situation occurs.

• In case you need me, call.
• In case she calls, tell her I am busy.
• In case anything goes wrong, who should we contact?

Comment l'utiliser : in case + clause (In case you need help, call this number.)

Synonymes : if

Expressions courantes : in case you need, in case anything happens, in case someone calls

au cas où, en prévision de

Indique qu’on prend une précaution face à un problème possible.

En anglais simple : Do something because an unwanted event or situation is possible.

• Keep a torch in case of a power cut.
• We checked again in case we had missed a name.
• She kept a spare key in case of trouble.

Comment l'utiliser : in case of + noun (Keep some cash in case of an emergency.); in case + clause (Check the list in case we forgot someone.)

Synonymes : as a precaution against

Expressions courantes : just in case, in case of fire, in case of emergency

en cas de, si

Présente une situation qui doit se produire pour qu’autre chose arrive.

En anglais simple : This introduces a situation that must happen for something else to follow.

• In case of illness, stay home.
• What happens in case the bus is late?
• The ticket is refunded in case of cancellation.

Comment l'utiliser : in case of + noun (In case of cancellation, you will receive a refund.); in case + clause (What should we do in case nobody arrives?)

Synonymes : if, in the event of

Expressions courantes : in case of failure, in case of illness, in case she comes