a present for Mary的用法和样例：
- Let's all chip in for a birthday present for Mary.
- She's buying a present for her boy-friend.
- He strung the coloured tiny stones together as a present for his sister.
- The children banded together to buy a present for their teacher.
- I'm going to buy Mother a present for her birthday.
- I've been chasing around town all morning looking for a present for her.