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.