Ответ:

1 A twin has a sister or brother with the same birth date.

2 An orphan is a child with no parents.

3 When you finish university you are a graduate.

4 After you retire, you become a pensioner and get money from the government.

5 A toddler is a child between two and four.

6 An infant is a child in its first year.

7 A tween is a child who is not yet a teenager.