Funny expression - Ce n'est pas demain la veille

When you doubt something will ever happen, or if it does, it will happen in a long time.

• In English you might say we will have to wait a long time before this happens / I'm not sure it will ever happen
• In French, cela n'arrivera pas avant longtemps / Cela arrivera peut-être un jour / Cela a peu de chance d'arriver prochainement.

You may also hear someone say : ce n'est pas demain la veille. If you translate literally 

• Ce n'est pas demain : it's not tomorrow
• la veille : the day before

So tomorrow is not the day before! (obviously !!!)

               Welcome to France, enjoy the French language!