The Pretérito perfecto (preterite form) is used to indicate that an action has been completed (it has had a beginning and an end point). These can be actions that can be taken as single events, actions that were part of a chain of events, actions repeated a very specific number of times, or actions that specifically state the beginning and end of an action. Therefore, the examples would be as follows:
1. Nosotros anduvimos rápidamente en la carretera (the sentence was in the present form and now has been changed to the preterite form for 1st person plural)
2. Juan dijo que sí (the verb in the present tense "decir" for 3rd person singular has been changed to the preterite form for 3rd person singular)
3. Yo puse el auricular en la mesa ("Poner" in the present form for the 1st person singular has been changed to the preterite form for the 1st person singular)
4. Tu le diste la carta a un amigo ("Dar" in the present form for the 2nd person singular has been changed to the preterite form for the 2nd person singular)
5. Nosotros estuvimos en la clase de inglés ("Estar" in the present form for the 1st person plural has been changed to the preterite form for the 1st person plural)
6. Michelle anduvo rápidamente en la carrera ("Andar" in the present form for the 3rd person singular has been changed to the preterite form for the 3rd person singular)
7. Nosotros supimos la verdad ("Saber" in the present form for the 3rd person plural has been changed to the preterite form 3rd person plural)
