Answer:
fueres
Explanation:
Si a Roma fueres haz lo que que vieres.
"In Rome, do as the Romans do"
1. Puso
2. Vino
3. trajeron
Ser and Estar both mean TO BE.
However, 'ser' is used in permanent situations, e.g: Soy alta = I am tall. Which is quite permanent because I cannot change the fact that I am tall.
'Estar', however is temporary situations, like mood. e.g: Estoy cansado = I am tired.
Hope this helped!