Explicación:
1. Sally is Tom's wife
2. Tom is Sally's husband
3. Kirsty is Sally's and Tom's daughter
4. Nick is their son
5. Sally is Nick's mother
6. Tom is Kirsty's father
7. Kirsty is Nick's sister
8. Nick is Kirsty’s brother
9. Sally and Tom are Kirsty and Nick’s parents
10. Kirsty and Nick are Tom and Sally’s children
