Answer the question using double object pronouns.
Question 17 : ¿Vas a comprar el libro nuevo para tu hermana? (Yes, I am going to buy it for her.)
Answer 17 : Sí, voy a comprárselo.
Rewrite the sentences using double object pronouns.
Question 18 : Ellos le cocinaron una hamburguesa para Carl. (They cooked it for him)
Answer 18 : Ellos se la cocinaron.
Question 19 : Nuestras maestras nos dieron un examen ayer. (They gave it to us yesterday)
Answer 19 : Nuestras maestras nos lo dieron.
Question 20 : Yo le di (gave) los boletos ayer. (I gave them to her yesterday)
Answer 20 : Yo se los di ayer.
Hope this helps!