Two sisters There are two sisters: Mary and Ann. Mary is seven years old and her sister Ann is only five years old. Mary goes to school and Ann doesn't so far. Once Mary comes from school and sees that her young sister writes something in the notebook. Mary asks her: "What are you doing?" - "I'm writing a letter to my friend" - answers Ann; -"How can you write the letter, if you can't write?" - asks Mary; -"It's not a problem, because my friend can't read" - answers Ann.