1. yo tengo las llaves para mi casa
2.ella tiene una calculadora en su mochila
3. I think this sentence is good you don't have to rewrite it
4. yo traigo el pasaporte a la aduana
Yes it is! other examples are mi,tu , su, nuestro and like you asked vuestro
all the things i wrote have no accents.
"su respuesta es incorrecta" is the correct answer.
