Describe the family that appears in the photograph!
The mother and father and your their sons.
Suggestion: In the picture you can see a mother, father and their two children, a daughter and a son.
The mother and father and their two children, a daughter and a son.
your = tu, your house = tu casa, your books = tus libros
their = belonging to them = su: their house = su casa, their books = sus libros