Final answer:
In Spanish, 'usted' is used when talking to someone you don't know well, while 'tú' is used for family members or good friends.
Step-by-step explanation:
In Spanish, you would use the pronoun 'usted' when talking to someone you don't know well.
For example, if you meet someone for the first time or if you are speaking to an authority figure, it is appropriate to use 'usted' to show respect and formality.
On the other hand, you would use 'tú' when talking to family members or good friends.
Learn more about Spanish pronouns