I would say para. Because para means "to" and the sentence is saying "my brother bought a bike to ride in the mountains"
The word to fill in the blank i pretty sure is ''Yo Te veo en clase''
Hope this helped! ;)
1. Jugar
2. Correr
3. Ir
4. Ver
5. Pasar
6. Nadar
7. Comer
8. Ver
Yo (nunca) estudiaba con Mariela porque no la conocía bien.
