What is the difference between direct and indirect object pronouns?

There is an easy way of knowing the difference between and when to use which object pronoun! To figure out the direct object of a sentence, simply ask yourself "who?" or "what?". For example: I bought the book. -What was bought? -The book Therefore the book is the direct object. Direct object pronouns then take the place of this direct object. I bought the book. J'ai acheté le livre. I bought it. Je l'ai acheté. To figure out the indirect object of a sentence, you can ask yourself the question "to whom?". I bought the book for Marie. -For whom was the book bought? -The book was bought for Marie. Therefore Marie is the indirect object. Indirect object pronouns then take the place of the indirect object. I bought the book for Marie. J'ai acheté le livre pour Marie. I bought the book for her. Je lui ai acheté le livre.