1、for the purpose of
Many people run for the purpose of losing weight.
5许多人为了减肥而跑步.
2、with the purpose of
He went to town with the purpose of buying a new television.
他进城的目的是买一台新电视机.
3、for the sake of 为了.起见
I stopped smoking for the sake of my health.
为了我的健康起见我戒烟了.
We ought to study hard for the sake of our motherland.
我们应该为了我们的祖国而努力学习.