31. Voluntarios su ocuparán este domingo para ayudar a nuestra comunidad.
32. Nos huiremos a la escuela mañana alas siete de la mañana.
I believe the answer you are looking for is C. limitaron which means limited. Translated it would be Although they limited the use of automobiles in the city, the air will remain contaminated. I hope this helps
3. is probably, I think PRIMO
Paraguay is not part of the las pampas region.