Respuesta :
Depends on how close you are with your teacher if you want to be formal Usted if informal use el or ella depending on gender.
What pronoun would you use if you are talking to your teacher?
Answer : usted
Explanation : The second formal person: usted, is used in Spain as a sign of respect to our interlocutor. To talk to a teacher should be used this pronoun. Usted.
Hope this helps!
[tex]\textit{\textbf{Spymore}}[/tex]