Bold answers:
1. Enrique quiere comprar una tabla de windsurf.
Answer 1: Quiere comprarla.
Enrique wants to buy a windsurfing board. He wants to buy it.
2. Están haciendo un viaje de tres semanas.
Answer 2: Están haciéndolo.
They are doing a trip of three weeks. They are doing it.
3. Tú tienes que conseguir los pasajes de avión.
Answer 3: Tienes que conseguirlos.
You have to get the plane tickets. You have to get them.
4. El huésped no entiende a una empleada.
Answer 4: No la entiende.
The guest does not understand an employee. He does not understand her.
5. Teresa me invita a la fiesta y también invita a Gustavo.
Answer 5: Nos invita.
Teresa invites me to the party and also invites Gustavo. She invites us.
6. El agente confirma la reservación.
Answer 6: La confirma.
The agent confirms the booking. He confirms it.