There are different dorms of 'tener' because the questions are referring to different people such as you or parents.
These 'tener' phrases compare to the way we express the same ideas in English by meaning the same thing but not translating into the same thing. Take ¿Tienes fr<span>ío? It translates to 'Do you have cold?' but it means 'Are you cold?' in Spanish.</span>
Ana, eres estudiante ? si, Juan, yo soy una estudiante de Argentina
sorry for the ? at the begining and the accent....i can't with my PC....
ser
soy
eres
es
somos
sois
son
hope I helped !