C’est le livre avec lequel j’étudie.
English: This is the book with which I study.
In French, 'les pronoms relatifs composés' (compound relative pronouns) are words like 'lequel', 'laquelle', 'lesquels', 'lesquelles', and their forms with prepositions (e.g., 'avec lequel'). They connect two sentences and refer to a noun mentioned before, adding more information.
Use these pronouns in French when you need to refer to a specific noun after a preposition (like 'avec', 'à', 'de', 'pour', etc.) and you want to give more information about it. They agree in gender and number with the noun they replace.
C’est le livre avec lequel j’étudie.
English: This is the book with which I study.
La maison dans laquelle il vit est grande.
English: The house in which he lives is big.
Voici les amis auxquels je pense.
English: Here are the friends I am thinking about.
La raison pour laquelle je pars est personnelle.
English: The reason why I am leaving is personal.