Preposition (après & derrière)

Definition: There is often confusion between the prepositions après and derrière and their opposites avant and devant.

Après and derrière are used in the following circumstances:

Après expresses something to do with time and means after. It can be used in front of a temporal expression, noun, pronoun, verb, or clause.
après 3h00
after 3:00
après le cours
after the class
après avoir mangé
after eating
après qu'il le fera
after he does it
Derrière expresses position or location (figurative or literal) and means behind. It can be used only in front of a noun or pronoun.
derrière la maison
behind the house
chercher derrière les apparences
look behind (beyond) appearances