Avant de +inf. and après +past inf. are structures which allow you to give an order of temporal succession of two events. To say that something happened/happens/will happen before or after something else, we talk about anteriority (before) and posteriority (after).
Example of anteriority: Before going to the cinema, we went to the restaurant.
Example of posteriority: After watching the movie, she went back home.
Note that in English, both anteriority and posteriority are structured in the same way:
before/ after + Verb ending in -ing.
In French, the structures differ depending on whether you refer to anteriority or posteriority.
1. Anteriority: Avant de + infinitive
Anteriority is used to say that an event happened/ happens/will happen before another event.
To express anteriority in French, you will need to use the structure: avant de + infinitive.
Example: Tu te laves les mains avant de manger.
You wash your hands before eating.
Note:
in that sentence, the same subject is doing both actions: you wash your hands, you eat.
the sentence can also be given the other way: Avant de manger, tu te laves les mains.
The preposition DE becomes D' if followed by a verb starting with a vowel.
With reflexive verbs
The reflexive pronoun must agree with the subject and is placed before the infinitive.
Example: Avant de nous coucher, nous allons regarder un film.
2. Posteriority: Après + past infinitive
Posteriority is used to say that an event happened/ happens/will happen after another event.
To express posteriority in French, you will need to use the structure: après followed by the past infinitive.
The Past Infinitive
The past infinitive is composed of the AUXILIARY (avoir or être) in the infinitive followed by the past participle of the main verb.
Example: Après avoir mangé, j'ai regardé un film. After eating, I watched a movie
Note:
the literal translation would be something like: After having eaten, I watched a movie, which does not sound very natural in English.
in that sentence, the same subject is doing both actions: I ate, I watched
the sentence can also be given the other way: J'ai regardé un film, après avoir mangé.
Using the correct auxiliary
Most verbs use AVOIR as an auxiliary, but there are a few verbs which use ÊTRE instead. The rule for verbs using ÊTRE is the same for all compound tenses. You can therefore refer back to the perfect tense to check the list of verbs which use ÊTRE as an auxiliary.
Be careful! With ÊTRE, the past participle must agree with the subject.
Example: Après être partie de la maison, elle a retrouvé ses amis.
With reflexive verbs
Just like in compound tenses, reflexive verbs use ÊTRE as an auxiliary.
The reflexive pronoun must agree with the subject and is placed before the infinitive (auxiliary).
Example: Après m'être habillée, je suis partie.
Be Careful!
It is also possible to express anteriority and posterity using avant que and après que.
If the subject is not the same in both parts of the sentence, then Avant que + subjunctive or Après que + indicative must be used!
You can check the subjunctive post to know more.
Recommendation:
For Students of A Level:
