一,
1.My sister is younger than her.
2.This ruler is longer than mine.
3.This tree is smaller than that one.
4.I am shorter than Yao Ming.
5.This bag is heavier than Xiaoming's.
二,
1.my book
2.his pen/ballpen/pencil
3.our football
4.her skirt
5.their classroom
6.its food
这个是我做的啊