短文：mary has four cousins.they are betty,peter,bill and ann.mary is the oldest of the five.betty is thirteen years old.sh

短文：mary has four cousins.they are betty,peter,bill and ann.mary is the oldest of the five.betty is thirteen years old.she is two years younger than mary and one year older than peter.bill is nine,and ann,the youngest ,is seven.
提问there are_____years between mary and peter.
peter is _____years old.