set an example for sb.是对的.set an example to sb.
其他用法有：
1.You should try to follow her example.[=try to do as she does]
2.Let that be an example to you![=let that show you what you should or should not do]
3.It's up to you to set an example.[=to behave in a way that shows other people how to behave]
4.She chooses to lead by example.[=to lead by behaving in a way that shows others how to behave]
如果要看跟详细的关于example的用法,就取参考资料看看.