2nd person plural...not in US!
My teacher says that the US does not concerns themselves with the 2nd person plural only Spain...is that true?
Yes, "you" is the same pronoun for both the singular and plural second person.
Yes, that is true. In Latin America ustedes is usually used instead of vosotros.
It is true. You just conjugate the verb to the 3rd person plural instead of the 2nd person plural.