In French grammar, les prépositions (prepositions) are little words that can answer questions like where, when, and with whom. They are used in combination with other words in a sentence to form a prepositional phrase. For example: dans la cuisine (in the kitchen) and avec mes amis (with my friends) are prepositional phrases that add information to a sentence.
Using a prepositional phrase in a French sentence is very easy: Write the preposition followed by the noun and then place it where it makes sense in the rest of your sentence, which is in most cases after the verb. For instance: Le chat dort sur le lit (The cat is sleeping on the bed) or La voiture est devant le garage (The car is in front of the garage).
You can add as many prepositional phrases as you want to a French sentence, like this: Le chat dort sur le lit, à coté de moi, avec sa balle. (The cat is sleeping on the bed, next to me, with his ball.) This sentence has three prepositional phrases.
When dealing with a complex preposition (one made of several words) that ends with de, keep in mind that de + le contracts into du, like for à coté du bus (next to the bus), and de + les contracts into des, like for loin des soucis quotidiens (far from the daily worries).
You can even use prepositions in questions when you combine them with a question word, like this: preposition + question word + rest of the question. Here are some examples of things you can ask using a preposition: à quelle heure (at what time), sur quoi (on what), pour qui (for whom), dans quelle (in which), and pour quelle raison (for what reason).