Article / Updated 03-26-2016
The most common French prepositions are à (to, at, in) and de (of, from, about). When these two prepositions are followed by the definite articles le and les, a contraction needs to be formed. (Note: There’s no contraction with à or de plus la or l’: à la, à l’, de la, de l’.)
Article
à + (le/les)
de + (le/les)
Le
au
du
Les
aux
des
À and de also contract with the different forms of lequel (which one):
Form of Lequel
à + (lequel)
de + (lequel)
Lequel
auquel
duquel
Lesquels
auxquels
desquels
Lesquelles
auxquelles
desquelles
There’s no contraction with laquelle: à laquelle, de laquelle.